A below-par Roger Federer beat unseeded Julien Benneteau in a tough fourth-round encounter to reach the quarter-finals of the French Open.

The world No 1 won his rain-hit match 6-4, 7-5, 7-5, and will now play Fernando Gonzalez for a place in the last four.

"He played a great match today but it was tough for both us with the conditions," Federer said.

The unseeded Benneteau had played more sets than any other player to get the last 16 but was not expected to pose any problems for the Swiss, who had won their only previous meeting in Cincinnati last year.

However, Benneteau did give the home fans, on a damp and overcast Philippe Chatrier Centre Court, something to cheer about when he broke Federer's serve at 3-5 down in the first set.

He failed to hold on to his own serve in the following game, though, sending a looping forehand wide under pressure from Federer's backhand.

Benneteau gifted Federer the first break of the second set by hitting an easy volley into the net and then playing a terrible drop shot. But once again the world No 1 failed to claim the set when serving at 5-3. This time the Frenchman had a point to force a tie-break before Federer struck again, moving two sets up as the rain started to fall.

Play resumed 90 minutes later and Federer continued to find life difficult, letting a match point slip at 5-4. But victory eventually came two games later when Federer finished off the match with a clinical overhead.

Benneteau said it had been an "exceptional experience" playing against Federer on the centre court, adding: "I was always behind, that was the problem today and I had few opportunities."