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 Novak Djokovic in four sets, a short while ago. Federer won the first set at 6-3, while Djokovic took the second at 6-3. Federer claimed the third set at 6-4 and the fourth set at 6-3.It was the first clash on grass between the two stars in their six-year rivalry. In other semi-final of the men's singles, Jo-Wilfried Isonga of France faces Andy Murray of Great Britain.