PARIS — Twice Roger Federer took an awkward spill Friday, leaving the regal champion sprawled on the clay that has tripped him up before.

The French Open can be humbling, as Federer well knows, but he'll try again for his first Roland Garros title Sunday against nemesis Rafael Nadal.

The top-ranked Federer endured some messy moments in the semifinal. Knocked down but not out, he wiped off the dirt and defeated unseeded Frenchman Gael Monfils 6-2, 5-7, 6-3, 7-5.

Nadal's earlier semifinal was close only by his standards: He lost 12 games and nearly lost a set. The king of clay beat No. 3-seeded Novak Djokovic 6-4, 6-2, 7-6 (3).

Nadal had lost only three games in each of his previous two matches. He's one win from becoming the first player since Bjorn Borg in 1981 to win four consecutive French Open titles, while Federer seeks the only Grand Slam title he has yet to win.

"Against Federer is special," Nadal said. "I will try and face history."

Nadal has beaten Federer at Roland Garros each of the past three years.

"It will be fun to play him again," Federer said. "I will try everything. I hope I will finally win here."

Ana Ivanovic and Dinara Safina will bid for their first Grand Slam title Saturday in the women's final.

For a brief time, the Nadal-Federer rematch appeared in jeopardy. Federer struggled against Monfils, especially in the final game of the second set, when he looked nervous serving and shanked a forehand on the final shot.

The partisan crowd roared, sensing a possible upset.

"I thought that would put pressure on Roger, but he didn't feel any pressure," Monfils said. "The crowd was behind me all the time. But then I was playing Roger, and French people love him as well."

Federer regained his composure and endured some brilliant play by the streaky Monfils down the stretch.

"He was magnificent," Federer said. "He was always trailing, but he hung tough, he fought back. It almost paid off. At the end, anything could have happened. So I'm very relieved."

Scrambling rallies twice sent Federer tumbling, while Monfils fell at least four times. Playing aggressively, Federer reached the net on 64 points — a lot on clay — and won 49.

The last was a crisp backhand volley to break Monfils in the final game. A jubilant Federer pumped his fist, then wearily leaned on the net and shook his head, glad to be still on his feet after 3 hours of taxing tennis.

Big serving helped Federer, who erased 10 of Monfils' 13 break-point chances. But Federer knows Nadal won't be so easily deterred.

For the fourth consecutive year in Paris, Federer seeks to become the sixth man to win all four Grand Slam events. Nadal defeated him in the semifinals in 2005, and in the final in 2006 and 2007.

This year the Spaniard appears more dominant than ever. He eliminated Djokovic from the tournament for the third consecutive year and improved to 27-0 at Roland Garros.

Borg watched from the first row behind the baseline and rose with the rest of the crowd to applaud when Nadal completed his latest victory.

"Unbelievable memories on this court," Nadal said. "It's emotional for me every year when I come back here."

Nadal became the first man since Ivan Lendl in 1987 to reach four consecutive French Open finals. The result prevented Djokovic from overtaking Nadal for the No. 2 ranking.

"The first two sets were very good today, almost perfect," Nadal said. "I was very dominant. I could hit the ball anywhere I wanted."

Nadal repeatedly lured Djokovic into long baseline rallies and won most of them, pushing the Serb from corner to corner with his muscular groundstrokes.

"He plays every point like it's a match point," Djokovic said.

Djokovic served poorly for much of the match and struggled to hold, facing 14 break points while Nadal faced only one in the first two sets.

With Nadal up two breaks in the third set at 3-0, Djokovic began to hit his groundstrokes even harder, and the high-risk tactic worked for a while. The Serb twice broke back, the second time to reach 5-all, and had a set point two games later, which Nadal saved with a forehand winner.

The crowd roared in support of Djokovic, hoping for more tennis. But in the tiebreaker Nadal raced to a 6-0 lead. He made several saves in the final rally before leaping to hit an overhead winner, then collapsed to his back in jubilation.

He rose covered in the clay he loves and punched the air. A disappointed Djokovic heaved his racket to the crowd, and both players won thunderous ovations as they headed for the exit.

Nadal summoned big serves on the rare occasions he was in trouble, and he scrambled about the court to hit improbable winners. In the final game of the first set, Djokovic appeared to hit a perfect drop shot, but Nadal charged forward to scoop it cross-court for a winner.

A chagrinned Djokovic applauded by tapping his strings, and two points later Nadal closed out the set.

Nadal briefly encountered resistance in the second set when he faced a break point serving at 2-1. He reacted by winning the next 11 points for a 5-1 lead.

"The first two sets, especially the second set, were pretty bad for me," Djokovic said. "I wasn't finding any rhythm and making a lot of unforced errors."

Straight sets are nothing new for Nadal, who has dropped only seven sets at Roland Garros — none in 2008. He has lost only 16 games in the past five rounds.