There is no question that the most talked-about topic heading into the U.S. Open is Serena Williams’ Grand Slam bid. Even if she does dominate the conversation, a certain “Big Four” of men’s tennis will provide plenty to discuss, too, as usual.

No. 1-seeded Novak Djokovic, for example, has been nearly as dominant as Williams in 2015. He won the Australian Open, was the runner-up at the French Open, then won Wimbledon, part of a 56-5 season that includes six titles and 10 consecutive appearances in tournament finals.

Given his excellence on hard courts, it’s hard to believe he’s earned the trophy only once at Flushing Meadows.

Five-time U.S. Open winner Roger Federer is 34, hasn’t won a Grand Slam championship in more than three years — and yet the No. 2-seeded Swiss star might just be as much of a threat as anyone to be in Arthur Ashe Stadium on the second Sunday. He made it all the way to the final at Wimbledon before losing to Djokovic, then beat the Serb for the hard-court Cincinnati Masters title this month.

“Still not very happy with my form and with my game,” Djokovic said after that loss to Federer, “but I have a week to work on it.”

No. 3 Andy Murray also defeated Djokovic in a hard-court final in August, at Montreal, and has made it to two semifinals and one final at this year’s majors. Like Djokovic and Federer, he is a past U.S. Open champion.

Rafael Nadal is worth keeping an eye on for the simple reason that no one quite knows how well he’ll play. He hardly has performed up to the standards that earned 14 Grand Slam titles, including two at the U.S. Open, and is seeded only No. 8. Nadal faces what could be a truly tough test in his opening match against 18-year-old Borna Coric. Get past that, then win three more matches, and Nadal could face Djokovic in the quarterfinals.

Here are other things to watch at the U.S. Open, which begins Monday in New York:

SHARAPOVA’S CHANCES

Maria Sharapova is a five-time major champion, including at the 2006 U.S. Open, but she’s hardly match-ready. She hasn’t competed since her semifinal loss to Williams at Wimbledon in July, sidelined since by an injured right leg. “You always have to believe in the ability to go through the little things that you might have,” Sharapova said. “There’s no athlete who’s ever 100 percent healthy.”

KYRGIOS AND WAWRINKA

Murray’s first-round opponent is Nick Kyrgios, a 20-year-old Australian who has been in the headlines for all the wrong reasons recently. During a match in August, a courtside microphone picked up Kyrgios telling his opponent, two-time major champion Stan Wawrinka, that another Australian player had slept with Wawrinka’s girlfriend. Kyrgios was fined by the ATP — and is on probation for the next six months, with an additional fine and a 28-day suspension threatened. Both Kyrgios and Wawrinka will be dealing with that episode’s fallout.

FEDERER’S NEW RETURN

Federer showed off a new, net-rushing, half-volley return in Cincinnati, so it will be interesting to see how much he uses that at the U.S. Open. “I’ll always mix it up,” he said, “and make it, I guess, uncomfortable for my opponent.”

FISH’S FAREWELL

Mardy Fish, a 32-year-old American once ranked in the top 10, will be playing the final tournament of his career after dealing with anxiety disorder, which forced him to withdraw from the 2012 U.S. Open. His first-round opponent is 102nd-ranked Marco Cecchinato of Italy, who has never played a Grand Slam match and is 0-6 in tour-level matches.

RAISING THE ROOF

Fans still have to sit out rain delays at Arthur Ashe Stadium for one more year, but they’ll get a break from the sun. The framework to support a retractable roof has been installed above the tournament’s main court, providing shade for part of the upper deck, which used to bake on hot days. The fully operational roof is scheduled to be in place for the 2016 U.S. Open. Four new video screens also have been added at Ashe, replacing the previous two.

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AP Sports Writer Rachel Cohen in New York contributed to this report.

NEW ORLEANS (AP) — Visiting residents on tidy porch stoops and sampling the fried chicken at a corner restaurant, President Barack Obama held out the people of New Orleans on Thursday as an extraordinary example of renewal and resilience 10 years after the devastation of Hurricane Katrina.

“There’s something in you guys that is just irrepressible,” Obama told hundreds of residents assembled at a bustling new community center in an area of the Lower 9th Ward that was once under 17 feet of water. “The people of New Orleans didn’t just inspire me, you inspired all of America.”

He held out the city’s comeback as a metaphor for what’s happening all across a nation that has moved from economic crisis to higher ground.

“Look at what’s happened here,” he declared, speaking of a transformed American city that was once “dark and underwater.”

Still, Obama acknowledged that much remains to be done. And after walking door to door in the historic Treme section of a city reborn from tragedy, he cautioned that “just because the housing is nice doesn’t mean our job is done.”

Areas of the city still suffer from high poverty, he said, and young people still take the wrong path.

There is more to be done to confront “structural inequities that existed long before the storm happened,” he added.

In his remarks at the community center, Obama blended the same themes of resilience and renewal that he drew from encounters with the sturdy residents he met along Magic Street and at other locations.

Leah Chase, the 92-year-old proprietor of Dooky Chase’s Restaurant, was one of those to chat with Obama. She pronounced herself a fan of the man, saying he’d handled “a rough road.”

Chase — who’s known as the “Queen of Creole Cuisine” — said, “That’s all you have to do: handle what’s handed to you,” voicing what could be a credo for the city.

Obama was clearly energized by his visits, at one point breaking into a song from “The Jeffersons” sitcom after meeting a young woman who calls herself “Ouisie.” He stopped for fried chicken at Willie Mae’s Scotch House, and pronounced the resulting grease stain on his suit a good indication that he’d enjoyed his stay in the city.

He held out the community center as “an example of what is possible when, in the face of tragedy and in the face of hardship, good people come together to lend a hand and, brick by brick, block by block, neighborhood by neighborhood, you build a better future.”

“And that more than any other reason is why I’ve come back here today,” he said.

Obama was a new U.S. senator when Katrina’s powerful winds and driving rain bore down on Louisiana on Aug. 29, 2005. The storm caused major damage to the Gulf Coast from Texas to central Florida while powering a storm surge that breached the system of levees meant to protect New Orleans from flooding.

Nearly 2,000 people died, most in New Orleans. Video of residents seeking refuge on rooftops, inside the Superdome and at the convention center dominated news coverage as Katrina came to symbolize government failure at every level.

In his speech, Obama said Katrina helped expose inequalities that long plagued New Orleans and left too many people, especially minorities, without good jobs, affordable health care or decent housing and too many kids growing up in the midst of violent crime and attending inefficient schools.

The setting of his address at the community center spoke to the stark contrasts that remain. It sits near nicely renovated homes but also next to a boarded-up wooden house. The area is filled with vacant lots where houses used to stand, so overgrown that local residents sometimes refer to it as the wilderness and worry about snakes hiding in the grass.

Colette Pichon Battle, executive director of Gulf Coast Center for Law & Policy, cautioned against slapping too happy a face on New Orleans, saying “rebuilding since the storm favors privileged private enterprise and this illusion of recovery is not progress.”

City residents, too, spoke of uneven recovery.

“I think we have a long way to go,” said Lisa Ross, 52, an appraiser. She said areas frequented by tourists have recovered tremendously but many neighborhoods have struggled.

Harold Washington, 54, a military retiree studying at Tulane, said the city is “better than it was.” But he was sad that children are now bused all over town rather than attending neighborhood schools.

Obama spoke hopefully of coming back to New Orleans after his presidency — when he can go to Mardi Gras and sample other delights.

“Right now,” he said, “I just go to meetings.”

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Benac reported from Washington. Associated Press writers Rebecca Santana and Kevin McGill in New Orleans and Melinda Deslatte in Baton Rouge, Louisiana, contributed to this report.

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Follow Darlene Superville on Twitter at http://www.twitter.com/dsupervilleap and Nancy Benac at http://twitter.com/nbenac

NEW YORK (AP) — Sprint is offering DirecTV customers one free year of cellphone service in a bold move aimed at the satellite TV company’s new owner, AT&T.

AT&T, which bought DirecTV for $48.5 billion in July, has been promoting a bundle that knocks $10 a month off a combined bill for video and wireless phone service. For a single line, the value of Sprint’s promotion is about $50 a month. It’s Sprint’s way of offering DirecTV customers a bundle without actually owning a video company.

Sprint, which is in the midst of a turnaround effort, has been making a range of promotional offers to lure customers. But so far, the Overland Park, Kansas, company hasn’t been as successful as T-Mobile, which went through its own turnaround.

T-Mobile is now the No. 3 wireless carrier in the U.S. after surpassing Sprint this year. In the April-June quarter, Sprint lost 12,000 customers, while T-Mobile gained 760,000, in “postpaid” phone plans, the ones offered to customers with good credit. But Sprint says it’s been reducing the size of its quarterly losses in customers and even saw gains in the months of May, June and July.

Craig Moffett, a senior analyst at MoffettNathanson, said the latest promotion is bold, but reckless.

“Sprint is already losing money and is burning through its remaining cash at an incredible rate,” he said. “Offering free service for a year will only make a bad situation worse.”

The free service will cost Sprint $600 per line, plus any charges to pay off rivals’ contract-termination fees or to finish off payments under monthly installment plans.

But Roger Entner, an analyst at Recon Analytics, said the costs are justified as investments for new customers.

“When you’re No. 4, you can’t afford to play it safe,” he said.

Dallas-based AT&T Inc. has been using the DirecTV service as a way to package wireless access and entertainment. Sprint Corp., which doesn’t have the entertainment component, isn’t willing to cede those customers to AT&T.

The latest promotion shows how aggressive phone companies have become as they try to lure customers from each other, given that most Americans now have cellphones.

Sprint’s offer is good for up to five lines on a single account, with each getting 2 gigabytes of data each month and unlimited calls and texts. It begins Friday and runs through Sept. 30. DirecTV customers must show some proof, like a DirecTV bill from the past 60 days, when signing up. But people can still sign up for DirecTV now to get the Sprint offer.

AT&T described Sprint’s offer as an act of desperation.

“This ranks right up there with a desperate Hail Mary pass to a petite defensive lineman,” the company said in a statement. “With Sprint’s network and the many asterisks on this deal, we’re feeling good about our offers.”

Sprint’s network isn’t as extensive as Verizon’s or AT&T’s, particularly in rural areas, and a free year of service isn’t good if it won’t work where you need it.

There are other conditions:

— Existing Sprint customers must add a new line of service to qualify. And both new and existing customers must buy or lease a new phone through Sprint; they cannot use one they already own.

— Customers must pay a one-time activation fee of $36, plus some monthly taxes and surcharges. Some taxes and surcharges are based on the number of lines rather than the cost of the plan, so customers wouldn’t save anything by paying nothing for service. But similar taxes and surcharges would apply at AT&T.

— The free offer is only good for a year, but phones typically take two years to pay off. For the second year, customers would pay $50 a month for a single line to $180 for five lines. That’s comparable to current rates.

— There’s no option for data beyond 2 gigabytes without paying higher fees for exceeding the cap — 1.5 cents per megabyte, or $15 per gigabyte. And these aren’t shared plans, so overage fees apply even if family members are below the cap. That said, 2 gigabytes is plenty for most people, unless they stream video.

BEIJING (AP) — Only when the running stopped and the picture-taking began did Usain Bolt finally meet his match.

Bolt blew past Justin Gatlin and everyone else Thursday night in the 200 meters to win his 10th career gold medal at the world championships.

What finally upended the 6-foot-5 Jamaican was a multitasking cameraman riding a two-wheeled scooter while videotaping Bolt’s victory lap. The scooter ran over the outcropping of a metal railing bolted to the edge of the track and bobbled off course — then slammed into the back of the fastest two legs on the planet.

Bolt’s legs came out from under him and he went down hard and landed on his backside. Then, smooth as silk, he somersaulted backward onto his feet, jogged a few steps, and reached down to make sure his left leg was OK.

He was no worse for wear — reporting just a few scrapes — but figured he’d try to make the evening at least a little more interesting.

“The rumor I’m trying to start right now is that Justin Gatlin paid him off,” Bolt said, while sitting next to Gatlin in the medalists’ news conference.

Gatlin’s response: “I want my money back. He didn’t complete the job.”

Indeed, it may take more than just a motivated opponent to finish off Bolt, who now has five gold medals at the Bird’s Nest, including the three he took at the 2008 Beijing Olympics when he set world records in the 100, 200 and the 400 relay.

The split-second scare with the scooter provided what Bolt’s season-best 19.55 seconds on the track did not.

Namely, drama.

This was billed as the second round of the Bolt vs. Gatlin series that produced the champion’s grittiest win four nights earlier. Bolt’s 0.01-second victory in the 100 came despite a year’s worth of injuries and off-form running that continued all the way through the semifinals.

Like most sequels, Part II didn’t live up to the original.

Running out of Lane 6, Bolt got off to a good start and worked smoothly into the curve, making up the lag to the runners to his outside and gathering steam as he headed into the turn. Leading at the halfway point, he opened a three-body-length lead over Gatlin early in the stretch, and the last 50 meters were simply for showing off.

Bolt coasted in and still won by 0.19 seconds. The winner used his thumbs to point at himself as he crossed the finish line and flashed his index finger: He’s No. 1 — just in case anyone had any doubts.

“What I really celebrated was, Justin Gatlin said earlier in the week that he was going to bring out something special for the 200 meters,” Bolt said. “I was like, ‘You don’t talk about my 200 meters like that.'”

Gatlin came into world championships dominating the sprints while Bolt was stuck on the sideline. The American was a favorite in the 100 meters, and Bolt took umbrage to the idea that Gatlin’s stumble over the last 15 meters gave that race away.

“Disrespectful,” Bolt called that notion. “I came out here and got it done.”

Once the 200-meter heats began, Bolt started getting stronger and Gatlin, by his own admission, started feeling tired.

“I’ve beaten him once before, and I hope to do it again,” Gatlin said about a 0.01-second victory at a meet in Rome in 2013. “He’s such a showman. You’ve got to give it to the guy for staying at the level he stays at. That’s hard to do.”

Gatlin’s silver added to gold medals won by two Americans — Christian Taylor in the triple jump and Allyson Felix in the 400. Anita Wlodarczyk of Poland won the women’s hammer throw with a championship-record toss of 80.85 meters (265 feet, 3 inches).

When Felix crossed the line, she tied Bolt for the most gold medals at the world championships with nine. That lasted all of about 10 minutes — until Bolt took No. 10 in the night’s final race.

Both sprinters are pointing toward Rio de Janeiro, where the Olympics are only 343 days away.

Something to think about: Bolt guessed if he’d pushed hard through the line Thursday night, he could have finished in the low 19.3s. He first got there at the 2008 Olympics, where he ran 19.30 to break Michael Johnson’s 12-year-old world record. Bolt has since improved that to 19.19.

“But one of my goals is to run under 19 seconds,” he said. “So if I want to run that, I have to really push myself next season.”

For the short term, his goal is to grab another gold in the 400 relay on Saturday — then get out of Beijing unscathed.

Not always as easy as it may seem.

After Bolt leaped up from his scary fall, he jogged back to the scooter driver to make sure he, too, was OK.

“I think he got the worst of it,” Bolt said.

When on the track with Bolt, most people do.

LOS ANGELES (AP) — Discovery is unleashing the first videos for its virtual reality network, Discovery VR, a fledgling service that is testing the limits and capabilities of the immersive format.

The videos debuting Thursday on DiscoveryVR.com, YouTube and on Android and iPhone apps, reveal some of the promise of the medium, which covers every angle you could possibly look and is navigable by moving a smartphone around you or even clicking and dragging the viewing angle around with a mouse.

In the short video, “Shark Shipwreck,” sharks swim around and above you — one even bumps the camera rig — as a narrator explains that the scent of food is being released by a diver nearby. Details that might not be obvious, like the parasitic fish that swim along the underbellies of sharks cruising overhead, are revealed when you swivel and look around.

In “Freeboarding: San Francisco,” viewers are put on the helmet of a skateboarder cruising down San Francisco’s famously winding Lombard Street. Looking backward or staring at fans lining the road doesn’t get you into an accident.

And you might be surprised at which direction outdoorsman Les Stroud enters the picture in “How to Survive the Wild,” because the forest scenery and burbling brook are entrancing on their own before he walks in unnoticed and starts discussing the day’s survival lesson.

Conal Byrne, Discovery Communication Inc.’s senior vice president of digital media, says the point of the project is to determine what works in the emerging format, including finding out what could make someone feel ill or disoriented.

“It needs to be repeated that we’re experimenting a lot,” Byrne says. “There are borders and boundaries that we’re really going to try to push.”

In addition to computers and mobile devices, the Discovery VR content can also be viewed using virtual reality headset devices, such as Google Cardboard and Samsung Gear VR, which are on sale now, as well as Facebook’s Oculus Rift, which is expected early next year.

Some content will be linked to existing shows such as “Survivorman,” ”Gold Rush” and “MythBusters” and others are original creations that will exist in categories like the thrill-seeking Adventure and placid Planet. Discovery VR plans to unveil new content every week at least for the next 12 months, Byrne says.

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Online:

Freeboarding: San Francisco video, http://bit.ly/1Jzc82G

Pacific Sunset: Half Moon Bay video, http://bit.ly/1V7DBwg

MythBusters: Shark Shipwreck video, http://bit.ly/1IduzEB

BAGHDAD (AP) — An Islamic State suicide bomber killed two Iraqi army generals on Thursday as they led forces against IS positions in the turbulent Anbar province west of Baghdad, military officials said.

They said the bomber drove his explosives-laden vehicle into the advancing troops north of Anbar’s provincial capital, Ramadi, killing the two generals and three soldiers. A military spokesman said on state television that 10 other soldiers were wounded. The officials spoke on condition of anonymity because they were not authorized to speak to the media.

The IS group captured Ramadi in May and also controls the nearby city of Fallujah.

A military statement read on Iraqi state television identified the two generals as Maj. Gen. Abdul-Rahman Abu-Regheef, deputy chief of operations in Anbar, and Brig. Gen. Sefeen Abdul-Maguid, commander of the 10th Army Division. The two were later given a military funeral at the Defense Ministry in Baghdad with Prime Minister Haider al-Abadi and Defense Minister Khaled al-Obeidi leading mourners.

An IS statement posted on Twitter accounts run by supporters claimed responsibility for the attack, but gave a different account, saying six fighters in four explosives-laden vehicles and armed with two heavy machine-guns carried out the attack.

Tens of soldiers were killed, including the two generals, it said without giving precise figures. The operation was designed to avenge the killing of a local commander in Anbar it identified as Abu Radi al-Ansari.

The Associated Press could not immediately verify the authenticity of the statement, but its language and phrasing is consistent with past IS claims of responsibility.

In neighboring Syria, meanwhile, IS militants seized five villages from rebel groups in the north as part of an advance toward the strategic town of Marea near the Turkish border. The Syrian Observatory for Human Rights and other activist groups said the IS carried out a suicide bombing on the outskirts of Marea amid fierce fighting in the area.

The Turkish Dogan news agency also reported renewed fighting between IS and rebels across the border from Kilis and said the U.S.-led coalition bombed IS targets in the region. Dogan video footage showed a large plume of smoke rising from across the border.

The IS advance is in the northern countryside of Aleppo province, near the area where Turkey and the United States have agreed to establish an IS-free safe zone.

Iraq’s government forces and allied Sunni and Shiite militiamen have been battling IS militants in Anbar for months but have only made modest gains against the group in the vast province that stretches west of Baghdad.

Speaking on state television, military spokesman Brig. Gen. Yahya al-Zobeidi sought to play down the psychological effect of the loss of the two generals. “We will not stop our operations and we will continue to advance,” he said.

The IS group controls about a third of Iraq and Syria. A U.S.-led coalition has been staging airstrikes against IS positions in both countries over the past year.

Government forces and allied militiamen are coming under mounting pressure from IS militants in the oil refinery town of Beiji, north of Baghdad. Government forces retook Beiji late last year, but the IS militants are on the offensive there again and now control about half of the town and the refinery.

Al-Abadi said this week that winning the ongoing battle over Beiji is key to defeating the IS group in Iraq.

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Associated Press writers Zeina Karam in Beirut and Suzan Fraser in Ankara, Turkey, contributed to this report.