Russian Maria Sharapova sits on the court after she twisted her left ankle during her quarterfinal of the Japan Pan Pacific Open Tennis Tournament against Petra Kvitova of the in Tokyo on?Thursday, Sept. 29, 2011.

Second-seeded Maria Sharapova was eliminated from the Pan Pacific Open in Tokyo yesterday when she was forced to retire in the first set of her quarterfinal match against Petra Kvitova.

With her Czech opponent leading 4-3 in the first set, Sharapova twisted her left ankle when serving in the eighth game. The Russian limped to her chair and pulled out after seeing a trainer.

"I hit a serve and then landed awkwardly on my left ankle," said Sharapova, who went to a hospital for an MRI. "I felt a sharp pain and next thing I knew I was on the floor. It swelled up immediately and I knew there was no way I could continue."

Yesterday's quarterfinal was a rematch of this year's Wimbledon final, where Kvitova beat Sharapova 6-3, 6-4 for her first major title.

"It's sad because we were both playing so well," Kvitova said. "It was a great match but I could see (the ankle) was really big. Hopefully, she will be OK."

Kvitova will now face fourth-ranked Vera Zvonareva of Russia, who defeated Maria Kirilenko 6-3, 6-3, in today's semifinal.

"I already played her three times, the last time in Madrid on clay when I beat her," Kvitova said. "She's a very good player. She has a great serve and hits the ball well so it will be a tough match."

Zvonareva had five aces in the match and improved to 6-0 in head-to-head matches against her unseeded compatriot Kirilenko.

"I'm really happy that my serve helped me today," Zvonareva said. "The first serve was good and my second serve even caused her some problems, and that made a big difference."

Kirilenko knocked out US Open champion Samantha Stosur of Australia on Tuesday and beat 12th-seeded Serb Ana Ivanovic on Wednesday, but struggled with her serve against Zvonareva and was broken three times.

"Maria is a great player and a great fighter, and proved it by beating two tough opponents on her way to the quarterfinals," Zvonareva said. "There is no secret to beating her. I just tried to make some shots that caused her some discomfort and was able to do that."

Last four

Also, third-seeded Victoria Azarenka of Belarus beat seventh-seeded Marion Bartoli of France 7-5, 6-0 to reach the last four. She will next face Poland's Agnieszka Radwanska, who ousted Kaia Kanepi 6-2, 7-6 (7). The Estonian had upset world No. 1 and top seed Carolina Wozniacki in the third round.

In Bangkok, Donald Young caused an upset at the Thailand Open yesterday with a 6-1, 6-7 (0), 7-5 victory over defending champion Guillermo Garcia-Lopez of Spain in the second round .

The fourth-seeded Spaniard, who received a first-round bye, saw his title defense crumble after two hours and 30 minutes of a baseline battle.

Victory for the 22-year-old Young secured a place in his second ATP quarterfinals, having reached the semifinals in Washington last month.

"It feels great to get a win like that," said Young, who missed an early chance to wrap up the match when serving at 5-3. "He won the tournament last year. It's a great scenario for me, it's great to move on into the quarterfinal.

Young next plays Go Soeda of Japan, a 6-2, 7-6 (9-7) winner over Tobias Kamke of Germany.

Garcia-Lopez lost a one-sided first set and then had a trainer attend to a broken toenail. But he said: "It is not the cause of my loss. I'm a professional tennis player. I just cannot play 100 percent all the time."