Top-ranked Maria Sharapova defeated Japan's Shinobu Asagoe 6-4, 6-1 to advance to the semifinals of the China Open on Friday, as Venus Williams withdrew because of a leg injury.
Sharapova lost her service game at the start of her match but immediately broke back and was in command for the rest of the contest. After Asagoe double-faulted to lose the first set, Sharapova promptly won the next five games, amassing an unassailable lead. The World No. 1 wrapped up the match in just over an hour, the AP says.
Williams withdrew ahead of her quarterfinal match against Poland's Marta Domachowska, citing an injury to her left knee sustained in her previous match.
"It is a new injury. I decided to withdraw this morning," she said, adding that she still expects to attend the WTA tournament in Guangzhou, China, next week.
Domachowska advanced to the semifinals and will face Germany's Anna-Lena Groenefeld, who eased past Peng Shuai of China, 7-5, 6-1.
Sharapova's semifinal opponent is fellow Russian Maria Kirilenko, who ended Chinese player Sun Tiantian's surprising run by beating her 6-1, 6-3.
Sun enjoyed strong crowd support, still basking from her shock upset of Serena Williams on Wednesday in the second round.
Serena Williams cited an existing knee injury as a factor in her defeat, in a tournament beset by injuries. Venus Williams said she was bothered by an injury she suffered Thursday during her win over Spain's Nuria Llagostera Vives.
World No. 2 Lindsay Davenport withdrew before the tournament began because of a lower back strain.