MASON, Ohio (AP) — Former U.S. Open champion Sam Stosur moved into the second round of the Western & Southern Open with a 6-1, 7-5 win over Svetlana Kuznetsova on Monday.
Stosur, who won the 2011 U.S. Open, lost in the round of 16 at the Rogers Cup in Toronto last week after winning the Southern California Open.
American Sloane Stephens outlasted qualifier Petra Martic, 6-2, 3-6, 6-3.
Former top-ranked singles player Martina Hingis and Daniela Hantuchova advanced to the second round in doubles with a 4-6, 6-4, 10-5 win over Anabel Medina Garrigues and Flavia Pennetta.
Serena Williams, Victoria Azarenka and Maria Sharapova will compete in the event together for the first time.
Top-ranked Williams, who won the Rogers Cup in Toronto on Sunday, has never won the Western & Southern, losing in quarterfinals last year to fifth-seeded Angelique Kerber.
“I’m motivated and happy and definitely feeling healthy,” Williams said Monday.
Second-ranked Azarenka pulled out of the Roger Cup last week to rest a sore back.
“I feel good,” Azarenka said. “The first (tournament back is always a little challenging to your body.”
In men’s play, Mardy Fish of the United States lost to 26th-ranked Philipp Kohlschreiber 7-5, 6-2.
American Brian Baker — in his first match since suffering a right knee injury at the Australian Open — pulled off 7-5, 6-3 upset of No. 63 Denis Istomin.
“It’s great to be back out there, for sure,” said Baker, who played in a challenger event last week. “That’s number one. Second tournament back since January, you’re always thankful to be back on the court.”
American Sam Querrey won the first-set tiebreaker before losing 6-7 (5), 6-3, 6-4 to No. 20 Janko Tipsarevic. Juan Monaco defeated Jurgen Melzer, 6-3, 6-2, and Jeremy Chardy beat qualifier Adrian Mannarino, 6-4, 6-3.
Nicloas Almagro became the first seeded player to fall, losing to Grigor Dimitrov, 7-6 (3), 6-4. Fabio Fognini was upset by Radek Stepanek, 6-2, 6-4.
In women’s upsets, wild-card Lauren Davis beat Klara Zakopalova, 7-6 (3), 7-6 (1), and wild-card Vania King, ranked 140th, stopped No. 38 Kristina Mladenovic, 6-3, 6-4.
Simona Halep rallied to defeat Su-Wei Hsieh 6-7 (5), 6-1, 6-2.
Sharapova is only one of the top three female players to earn a Western & Southern title, winning in 2011.
The event is her first since losing in the second round at Wimbledon. She’s also been bothered by a hip injury.
“Everything is feeling fine,” the third-ranked Sharapova said. “I’m at the stage of my career where I have the luxury of making sure. I love playing a full schedule, but I’d rather come in here feeling good and healthy. I haven’t played in weeks, so I might be a little rusty.”