BEIJING &

Roger Federer's bid for his first Olympic singles medal ended today when he lost to American James Blake.




Soon after, Serena Williams was also eliminated in a tournament that had been upset-free through three rounds. No. 5-seeded Elena Dementieva of Russia, who won a silver medal in Sydney in 2000, raced to a 5-0 lead in the final set and held on to beat Williams 3-6, 6-4, 6-3.




With the sort of lackluster performance once unthinkable for Federer, he was eliminated in the quarterfinals 6-4, 7-6 (2).




Blake's victory was a stunner in that he had won only a single set in eight previous matches against Federer. But the top-seeded Federer has been battling a yearlong slump that has left him stalled at 12 major titles, two shy of Pete Sampras' record.




His Wimbledon reign ended last month, and he came to Beijing knowing he would lose the No. — ranking to Rafael Nadal next week after 41/2 years on top.




Federer's latest defeat means no rematch in Sunday's final against Nadal, who won in epic fashion when they met for the Wimbledon title.




Federer had been seeking his first Olympic medal after losing in the singles semifinals in Sydney and in the second round in Athens. He was scheduled to play a quarterfinal doubles match later today with Swiss partner Stanislas Wawrinka.




The upset was sweet for the No. 8-seeded Blake, a first-time Olympian at 28 and the lone U.S. male to survive the first round of singles.




The match began after a rain delay of — hours, 35 minutes, and Federer seemed off his game from the start. His forehand &

once the sport's most feared &

was unreliable, and he repeatedly struggled to hold serve.




Blake earned the first break in the final game of the opening set. On set point, Federer left his feet for a spectacular backhand save that extended the rally, but with his next shot he floated an easy backhand into the net.




His shoulders sagging, he was broken again two games later and fell behind 3-0 in the second set.




Federer finally showed life by breaking back in the fifth game and holding the rest of the way to reach 6-all. But Blake played a flawless tiebreaker, while Federer made two unforced errors and popped up a volley.




When Federer sailed a return long on match point, Blake screamed "Yeah!" Federer ripped off his headband and walked head down to the net.




It just wasn't Federer's night: He even went 0-4 on replay challenges.




The No. 4-seeded Williams tried to rally against Dementieva in the final set, overcoming 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. The loss came after the U.S. team had won 12 consecutive matches over the past three days.




Williams remained in contention for a doubles medal and was to play a second-round match later with her sister Venus. They won a gold in doubles in 2000 in Sydney.