Roger Federer has been slowed by health issues, but he briefly left the court Monday because of a back injury and had spectators at a loss of words wondering whether he would return.

Federer's back began bothering him early in his fourth-round match. He blamed the cool, windy weather and the lingering effects of a five-set win over Julien Benneteau three days earlier.

After an eight-minute delay, Federer resumed and went on to beat Xavier Malisse 7-6 (1), 6-1, 4-6, 6-3. With this victory Federer reached his 33^rd consecutive Grand Slam quarterfinal, extending his Open era record.

Federer's serve lacked its usual velocity, but his play seemed otherwise unaffected by the bothersome back. An hour after the victory, he said he already felt much better.

While Federer has felt a back twinge or other discomfort on occasion, he has also played in 51 consecutive Grand Slam tournaments, a true testament to his durability.

Joining him in the quarterfinals will be defending champion and No.1 ranked seed, Novak Djokovic, who had little trouble with fellow Serb Victor Troicki.

Djokovic dispatched Troicki in just 90 minutes by breaking him six times en route to a 6-3, 6-1, 6-3 victory. Djokovic won 16 of his 19 approaches to the net and hit 31 winners overall, compared with 15 for Troicki.

The top-ranked Djokovic will next face the winner of the meeting between Richard Gasquet and Florian Mayer, whose match was among those suspended for the day because of persistent rain.