LA: Maria losses to Petrova

Defending champion Maria Sharapova lost to Russian compatriot Nadia Petrova 6-1, 6-2 for the first time in four career meetings, and finished second in the Green group, having won fewer sets than Davenport.

"It's hard to get going when your body isn't there and your mind is on your pillow," said Sharapova, who was still tired after beating Davenport 6-3, 5-7, 6-4 Thursday night.

Mauresmo also advanced by finishing second in the Black group with a 2-1 mark. She will play Sharapova in the semifinals.

"All the soldiers are down and it will be whoever can get up," Sharapova said.

The 18-year-old star hasn't won a tournament since June, and has been bothered by a right pectoral muscle injury since August.

"I didn't expect myself to play great tennis after not playing in a while," she said.

Petrova had eight aces, won 84 percent of her first-serve points, and saved all three break points against her in the hour-long match.

"Today, everything worked for me and I returned much better than I used to against her," she said.