BEIJING (AP) - Serena Williams has lost her quarterfinal match at the Olympics to Elena Dementieva of Russia.

Dementieva, who won a Silver in Sydney in 2000, beat Williams 3-6, 6-4, 6-3 in their singles match Thursday night.

Williams now pins her medal hopes on doubles. She was to play a second-round doubles match later with sister Venus. They won gold in doubles in Sydney.

The fourth-seeded Serena tried to rally from a 5-0 deficit in the final set against the No. 5-seeded Dementieva.

Williams overcame two match points during an 18-point game to hold for 5-3. But Dementieva held at love in the next game, sealing the victory when Williams pushed a volley wide.