Top-seeded Serena Williams and Wimbledon champion Maria Sharapova reached the China Open semifinals when their opponents had to stop playing Friday because of ankle injuries.

Sharapova will face U.S. Open champion Svetlana Kuznetsova in an all-Russian semifinal. Kuznetsova, seeded second, beat Argentina's Gisela Dulko 6-4, 6-2 in the quarterfinals.

Williams will meet fourth-seeded Vera Zvonareva of Russia. She defeated Anabel Medina Garrigues of Spain 6-2, 6-3 in the last quarterfinal.

Williams was leading 6-2, 4-1 when Nadia Petrova called for a trainer. Williams had been in control with groundstrokes that sent the Russian teetering from one side of the court to the other.

"My expectation is definitely to get to the final," Williams said. "I think I played solid today. I definitely think I can play better."

Petrova said she hurt her left ankle in the third game when she was surging forward to hit what she thought would be a volley from Williams but had to change direction when her opponent hit a passing shot.

"I was more thinking about my ankle than about the game," Petrova said.

Sharapova, seeded third, advanced when seventh-seeded Jelena Jankovic of Serbia-Montenegro retired during the first set because of an injury to her right ankle from the first round. Sharapova was ahead 5-2 and preparing to serve out the set when Jankovic sought medical attention. When play resumed, Sharapova took a 40-15 lead before Jankovic quit.

Sharapova has yet to face a strong challenge after a first-round bye and a 6-1, 6-1 victory over Tatiana Panova in the second round.

"I definitely think for me it's an advantage," she said.

Kuznetsova enjoyed a quick result after struggling in a three-setter the previous day against China's Li Na.

"I'm getting more used to the center court," she said. "Before, nobody told me the center court was so much faster than the other courts."

Source: agencies