Swiss star Roger Federer has entered the men's singles final of the Wimbledon Tennis Championsips. In the first semi-final in London today, he defeated defending champion and top seed Novak Djokovic of Serbia in four sets. Federer won 6-3, 3-6, 6-4, 6-3. Six-time champion is looking to equal Pete Sampras's record of seven titles. It was the first clash on grass between the two stars in their six-year rivalry. In the other semi-final of the men's singles, Jo-Wilfried Isonga of France is playing against Andy Murray of Great Britain.