Second-seeded Maria Sharapova set up a possible quarterfinal match with Serena Williams by beating Slovakia's Daniela Hantuchova 6-2, 2-6, 6-4 on Wednesday at the Bank of the West Classic.
The fifth-ranked Sharapova, who reached the Wimbledon final, questioned an out call that would have ended the match. She regrouped and won the next two points to set up the possible match between two former world No. 1s.
"I feel great," Sharapova told the crowd as she left the court to a huge ovation.
Williams, playing in her first tournament on American soil since the 2009 U.S. Open, meets Maria Kirilenko on Thursday afternoon.
France's Marion Bartoli reached her seventh quarterfinal of the year, beating Rebecca Marino of Canada 6-4, 6-3.
The ninth-ranked Bartoli, who won this event two years ago, has won 18 of her last 21 matches.
"I love this tournament. It's a great way for me to start back," Bartoli said. "I lost to Rebecca last year in Quebec, so it was good for me to take revenge. I really felt like I was moving well. I was hitting the ball well for having three weeks off."
Marino, ranked 40th, beat Bartoli at Quebec City last year â€” her only win over a top-20 player.
In other matches, eighth-seeded Dominika Cibulkova of Slovakia beat American Christina McHale 6-4, 2-6, 6-3, and fifth-seeded Agnieszka Radwanska of Poland topped taiwan's Chang Kai-chen 6-4, 3-6, 6-0.
"It was really difficult to play," Cibulkova said. "I didn't play my best and it's not always easy to win matches like this."
The 20th-ranked Cibulkova reached her seventh quarterfinal of the year and will meet the winner of Thursday's match between top-seeded and defending champion Victoria Azarenka and qualifier Marina Erakovic.
"Sometimes a match like this gives you more confidence because you have to fight and play through it when you are struggling. Now in the next match, you can play even better knowing you just won a real tough match."