LONDON (AFP) - Serena Williams clinched her third Wimbledon title and 11th Grand Slam crown with a 7-6 (7/3), 6-2 victory over sister Venus, the defending champion, here on Saturday. The victory added to her 2002 and 2003 wins at the All England Club and shattered Venus's hopes of a hat-trick of titles and sixth overall which would have taken her level with Billie Jean King. Saturday's final was the fourth all-Williams title match-up at Wimbledon and eighth in all Grand Slams with the win giving Serena the edge in head-to-head meetings at 11-10. Serve dominated the first set with 27-year-old Serena fighting off the only two break points in the eighth game and it was the younger of the two sisters who seized control of the tiebreak. Serena went to three set points by forcing Venus to scramble from side to side before putting away a powerful crosscourt forehand. Venus saved the first set point but was powerless when a pinpoint lob from her sister left her stranded at the net. It was the first set Venus had dropped at Wimbledon since the third round in 2007, a run of 34 consecutive winning sets. Serena, who had saved match point in her marathon semi-final win over Elena Dementieva, carved out her first set point when Venus double-faulted to hand her a 4-2 lead and revenge for last year's final defeat to her sister looked likely. Second seed Serena held to love, backed-up by her 12th ace of the match, to lead 5-2.She then wasted three match points in the eighth game but clinched the title when Venus netted with a forehand. Earlier, Roger Federer reached a record 20th Grand Slam final, and a seventh straight Wimbledon title match Friday, while Andy Roddick ended Andy Murray's bid to become the first British champion here since 1936.Five-time champion Federer coasted to a 7-6 (7/3), 7-5, 6-3 win over German veteran Tommy Haas and will be chasing a record 15th Grand Slam crown on Sunday when he tackles old rival Roddick.The American sixth seed put an end to the hype and hysteria in Britain with a 6-4, 4-6, 7-6 (9/7), 7-6 (7/5) win over third seed Murray who had been hoping be the first British men's champion since Fred Perry 73 years ago. Federer will be the overwhelming favourite for the title having beaten Roddick 18 times in 20 matches, including the 2004 and 2005 finals here. Watched by Grand Slam greats Bjorn Borg and Rod Laver, comfortably installed in the Royal Box, the world number two put on a magnificent show of serving against 31-year-old Haas, not giving up a single break point. "Tommy played great so I knew that there was a danger. I'm happy with my performance and it's unbelievable to be in another final," said Federer. "I have had a lot of pressure over the years but I am looking forward to another great match and a chance to get into the history books."Federer said he was looking ahead to the challenge of the final. "I have had great matches with Roddick. You can never underestimate him with that serve," he said.Haas was full of praise for the Swiss."There aren't really any weaknesses. He moves in such a smooth way and has such good defensive play. The slice bites a lot," said the German. "When you think sometimes you might get a relatively easy volley, he kind of either dinks it in front of you, or he made two spectacular slice lobs over my head at important points."Roddick will be playing in his first major final since 2006. "I had to play my best tennis today. I can't say enough good things about Andy's game but I can play some tennis sometimes," said Roddick, who had won just two of his previous eight meetings with the Scot. "Not many people gave me a chance but I knew if I stayed the course I had a shot." Murray out-aced Roddick 25-21, but the American's awesome power in the tiebreaks proved decisive. The third seed saved a match point in the fourth set breaker but went down to defeat when he netted an approach. Four years younger than Roddick and five years younger than Federer, Murray believes it's just a matter of time before he wins a major. "I think I have a chance. I believe I can win a Grand Slam, whether it's Wimbledon or US Open or Australia or whatever, I'm going to give myself chances." Murray said he refused to be too downhearted by his defeat to Roddick. "I thought I played well. I had fewer unforced errors (20-24), made more aces (25-21) and hit more winners (76-64) but it came down to just a few points on his serve," said the world number three. Earlier Roger Federer reached a record 20th Grand Slam final and a seventh straight Wimbledon title match with a 7-6 (7/3), 7-5, 6-3 win over German veteran Tommy Haas in the semi-finals on Friday. Five-time Wimbledon champion Federer, who is chasing a record 15th Grand Slam crown, now tackles either Britain's Andy Murray or Andy Roddick of the United States in Sunday's final. Watched by Grand Slam greats Bjorn Borg and Rod Laver, comfortably installed in the Royal Box, the world number two put on a magnificent show of serving against the German 31-year-old, not giving up a single break point. "Tommy played great so I knew that there was a danger. I'm happy with my performance and it's unbelievable to be in another final," said Federer. "I have had a lot of pressure over the years but I am looking forward to another great match and a chance to get into the history books."Federer said he was looking ahead to the challenge of the final. "I have had great matches with Roddick. You can never underestimate him with that serve," he said. "Murray's at home. My record against him is not that good. He's shown over the last 18 months that he can be a Grand Slam contender." The opening set on Friday was dominated by serve, but the Swiss second seed was the strongest in the tiebreak. He went to three set points when Haas unleashed a loose forehand with the world number two wrapping up the set when the German, stranded behind the baseline, pushed a backhand into the net.It was the dream start for the five-time champion after the nightmare beginning he suffered against the same opponent at the French Open last month when he had to recover from losing the first two sets in the fourth round.Former world number two Haas, playing in his first Wimbledon semi-final, had to save a set point, which was also the first break point of the match, at 4-5 in the second set.But the Swiss broke through in the 12th game for a two-sets lead when another Haas forehand went long.Haas cracked for the last time in the eighth game of the third set when he netted an easy approach having saved four break points.Federer then wrapped up the semi-final in just over two hours on his first match point with a spectacular, athletic smash. In Friday's second semi-final, third seed Murray will be looking to become the first British men's finalist since Bunny Austin in 1938. Fred Perry was the last British men's champion in 1936. Roddick, the sixth seed and 2003 US Open winner, was runner-up here in 2004 and 2005, losing both finals to Federer.