Roger Federer's misery goes on

Beijing: Top seed Roger Federer was beaten 6-4 7-6 by American James Blake in the quarterfinals of the Olympic men's singles on Thursday.

The Swiss produced an error-strewn display under the Centre Court lights after a long rain delay and was outplayed as Blake claimed his first victory against Federer in nine meetings.

Defeat continued Federer's miserable season and leaves the 27-year-old running out of chances to win an Olympic medal, although he is still in the doubles here.

Last month he lost his Wimbledon title to Rafael Nadal and he will cede his world number one ranking to the Spaniard on Monday.

Blake said he always believed he could break his duck against the 12-times grand slam champion.

"I always believed in myself," said Blake, who is now just one victory away from a guaranteed medal. "I'd lost to him eight, nine, 10, 50 times, I don't know how many, but I had the feeling it could be my day today."

Eighth seed Blake played two superb baseline rallies to close out the first set as Federer served at 5-4 down.

Federer then fell 3-0 down in the second set before battling back to 3-3.

Luck seemed to be on Federer's side when a nervy volley dribbled over off the net tape when Blake was two points away from victory in the 12th game of the second set.

Match point

However, the inspired American would not be denied, surging 6-2 ahead in the tiebreak and sealing victory on his first match point.

"He didn't play a good first game and that put me up straight away. I played loose and free and I always fancy my chances on the 5-4 game," Blake said.

"When he got that net cord I started wondering if it would turn around and he would come back playing like the best player in the world. But I know I can beat the best in the world on my day and today I proved it."

Blake will play either Chile's Fernando Gonzalez or Frenchman Paul-Henri Mathieu for a place in the final.

Former winner out

Double Olympic champion Venus Williams was beaten 7-5 7-5 by China's Li Na in the quarterfinal of the women's singles yesterday.

Venus, the seventh seed, crashed out to an inspired home favourite who immediately offered the victory as a present to the Beijing Olympics.

"Venus was the best player in the world, she has just won Wimbledon," said Li. "She has big serves that I can't receive but I told myself to calm down and play my best.

"Wow! You can't see this kind of crowd anywhere else. It helped me and pushed me a lot. This is a present I give to the Beijing Olympic Games but I have no time to celebrate. I have more matches to go."

Venus raced into a 3-0 lead in the opening set but Li, the first Chinese player to reach the top 20 in the world rankings, proved she had the stomach for a fight.

Venus's sister Serena suffered a shock quarter-final defeat by Russian Elena Dementieva going down 3-6 6-4 6-3.

Serena had seemed destined for Saturday's gold medal match but her challenge evaporated after a good start.

Dementieva, a singles silver medal winner at the Sydney Olympics, gradually came to terms with the fourth seed's power, crunching winners from the baseline to take the second set.

The Russian forged ahead in the decider. She squandered two match points at 5-2 but made no mistake a game later when she forced Williams into a volley error at match point.

Results

Men's singles

Quarterfinals:
James Blake (USA x8) bt Roger Federer (SUI x1) 6-4, 7-6 (7/2)

Women's singles

Quarterfinals:
Elena Dementieva (RUS x5) bt Serena Williams (USA x4) 3-6, 6-4, 6-3
Vera Zvonareva (RUS x9) bt Sybille Bammer (AUT) 3-6, 6-3, 6-3
Li Na (CHN) bt Venus Williams (USA x7) 7-5, 7-5