Both Rafael Nadal and Roger Federer faced stiff resistance from their opponents in the fourth round of the 2008 US Open tennis tournament.

On September 1 2008 Nadal had to do his best to win against host favourite Sam Querrey who played the best tennis in his career. The match started well for Nadal, who imposed his usual fast tempo to win the first set 6-2.

When it all looked like yet another triumph for Nadal, Querrey found new strengths in the support from the home crowd and managed to break Nadal's service and the second set ended with a surprise win of the American over Nadal (7-5).

It was not the first time the two played against each other and it was certainly not the first time Nadal lost a set to the American, but Querrey's game was superb and for the first time since the start of the season the Spaniard was close to losing the match.

The third set ended in a tie break, where Nadal's experience got the better of Querrey and the world number one won in by a scoreline of 7-2.

Un the end, the pressure proved to be too much for Querrey and the fourth set was easily won by Nadal (6-3). In the quarterfinals Nadal, would play against another American, Mardy Fish.

If Nadal had a difficult time against Querrey, Federer was having a nightmare against Russian Igor Andreev, prevailing but only a full five-set match was played.

The first set was surprisingly won by the Russian in a tie break. The second set also went all the way, but went to Federer. The Swiss former world number one won the third set 6-3, only to lose the fourth by the same scoreline.

The fifth and decisive set was when Federer had to show why he is one of the three main contenders for the title and he won it. The result at the end was a 6-7, 7-6, 6-3, 3-6, 6-3 win for Federer, who conceeded after the match that he did no play his best tennis. In the quarterfinals, Federer will meet Luxemburg's Gilles Muller.

The other two quarterfinal couples are Novak Djokovic, the Serbian who won this year's Australian Open, versus former US Open winner Andy Roddick, while Britain's top player Andy Murray against Argentinian Juan Martin Del Potro, who is currently on a 23-match winning streak after winning four ATP tour titles in July-August.