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Federer has beaten Monfils on each of their three previous meetings

World number one Roger Federer will play Gael Monfils in the French Open semi-finals after both men came through their last-eight matches in four sets.

Top seed Federer struggled early on against Fernando Gonzalez before coming through 2-6 6-2 6-3 6-4.

And he will face Monfils for a place in the final after the unseeded Frenchman beat David Ferrer 6-3 3-6 6-3 6-1.

Monfils eventually overwhelmed fifth seed Ferrer and is the first Frenchman to reach the last four since 2001.

No home singles player has made the semi-finals at Roland Garros since Sebastien Grosjean seven years ago.

Monfils, the 2004 junior champion, is bidding for a title that has eluded the French since Yannick Noah's triumph in 1983.

I was really happy the way I came back - I really got on a roll, played great and was able to dominate him at times Roger Federer

Monfils stepped up a gear thereafter, though, to complete the win in two hours and 27 minutes.

"I ran well on court and I wanted to take the ball early. I played great tennis today," he said.

"I prepared really well. I tried to stay concentrated and with my family and the crowd behind me, I felt very strong."

In the other semi-final, defending champion Rafael Nadal takes on third seed Novak Djokovic.

Federer is into his 16 consecutive Grand Slam semi-final and remains on course for his third successive final at Roland Garros despite an uncharacteristically languid start against Gonzalez.

"It's always a great pleasure being in the last four," Federer said. "It's really where it gets most interesting.

The top seed had his serve broken three times in the first set as the Chilean continued where he left off in his last meeting with Federer - a 3-6 7-6 7-5 triumph in the 2007 Masters Cup in Shanghai.

"I was a bit afraid because the match was not going the way I wanted. I was really under pressure in the first set. I felt uncomfortable. I was missing a lot of shots, and he defended well."

But Federer, who lost the first set of his second round tie against Albert Montanes before storming through to win 6-7 (5-7) 6-1 6-0 6-4, rallied in the second set.

Gonzalez continued to rely almost solely on a wide serve followed by thumping groundstrokes from the baseline and Federer swiftly punished his opponent's lack of variety.

606: DEBATE Roger is struggling and not at his best, but does that mean u can count him out mrbigboo

A litany of unforced errors from Gonzalez ensured Federer did not need to hit the type of form that, most notably, saw him destroy Mario Ancic in the third round.

He broke Gonzalez's first service game to go 2-0 up and, with his serve at times completely outwitting the number 24 seed, Federer cruised to the third set.

The 26-year-old's victory was effectively sealed when he broke at 1-1 in the fourth set and, with Gonzalez failing to challenge Federer's server, the conclusion was a mere formality.

"I was really happy the way I came back. I really got on a roll, played great and was able to dominate him at times."

Federer has beaten Monfils on each of their three previous meetings including a 6-3 6-4 win on the Monte Carlo clay this year.