Four-time defending champion Roger Federer may have had to scrape through his 4^th round match, but he has advanced to the US Open semi-finals more easily by beating 130th-ranked Gilles Muller 7-6 (7-5) 6-4 7-6 (7-5).

The brilliant Swiss, who came into the tournament as second seed, extended his US Open winning streak to 32 matches, and will await his next opponent, winner of another quarter-final sure to be a epic between Serbian third seed Novak Djokovic and US eighth seed Andy Roddick.

If Federer is successful in winning his 13th grand slam title he will come to within one of the all-time record set by Pete Sampras.

But first he must make it to the Final. Federer has won 15 of seventeen matches played  against Roddick and won six of eight meetings with Djokovic, including last year's US Open final.

The other men's semi-final will be played between  British sixth seed Andy Murray and  Spanish world No.1 Rafael Nadal, who chases his third slam trophy in a row after beating Federer in both the French Open and Wimbledon finals.

Tags: Roger Federer, Tennis, US Open