PARIS — Roger Federer knows full well, of course, that Rafael Nadal is no longer around this year to befuddle him, to beat him, to stand between him and a French Open title.

Federer insists he is not thinking about that, not thinking ahead. Still, Federer sure did play as if preoccupied for the better part of two hours yesterday, dropping the first two sets of his fourth-round match against 63rd-ranked Tommy Haas of Germany.

One point from letting Haas serve for the victory, Federer conjured up one particularly spectacular forehand that managed to change the entire flow of things. That shot spurred a run of nine consecutive games for Federer, sending him to a 6-7 (4), 5-7, 6-4, 6-0, 6-2 victory over Haas and a berth in the quarterfinals at Roland Garros.

"I knew I was going to look back on that shot. That saved me," Federer said. "I was in quite some danger."

But he escaped. With two more victories, Federer will reach a fourth consecutive final at the French Open, the only Grand Slam championship he hasn't won. Federer lost to Nadal in each of the past three finals and in the 2005 semifinals, but the Spaniard's 31-match winning streak at the clay-court major tournament ended Sunday against Robin Soderling.

"You're aware of it," Federer said. "Definitely changes it up, if I were to make the final. But we're not there yet, so honestly it hasn't changed a whole lot for me."

Federer now tries to reach the semifinals at a 20th Grand Slam event in a row, which would extend his own record, when he meets 11th-seeded Gael Monfils of France, a 6-4, 6-2, 6-3 winner over No. 6 Andy Roddick, the last American man in the tournament.

Federer is 4-0 against Monfils, including a victory in the French Open semifinals a year ago. Monfils dominated Roddick, even out-acing him 17-4, and Roddick began complaining in the second set that it was too dark to see.

"Don't tell me what's OK and what's not," the 2003 U.S. Open champion snapped at chair umpire Enric Molina. "You're not the one playing."

It was the day's last match on Court Suzanne Lenglen, and the start was delayed by No. 5 Jelena Jankovic's loss to the 41st-ranked Sorana Cirstea of Romania, 3-6, 6-0, 9-7, which lasted 2 hours, 44 minutes.

"It wasn't easy at the end," said Cirstea, two points from defeat when Jankovic served for the match at 5-4, 30-love in the third set. "I saw she was tired, also. So I knew it was also a little bit mental: Who is going to stay stronger?"

Elsewhere, 2002 champion Serena Williams beat No. 24 Aleksandra Wozniak of Canada, 6-1, 6-2; No. 7 Svetlana Kuznetsova defeated No. 12 Agnieszka Radwanska of Poland, 6-4, 1-6, 6-1; and No. 30 Samantha Stosur beat Virginie Razzano of France, 6-1, 6-2.

"This," Williams said, "is when everything counts."

No one knows that better than Federer, whose 13 major championships are one shy of Pete Sampras' record. With Nadal, Roddick and No. 4 Novak Djokovic all gone, Federer is the only man left with a Grand Slam title.

"For a lot of players," Federer said, "I think it must be quite a big opportunity, and their heads must be spinning right now."

The other matchup on his half of the draw is No. 5 Juan Martin del Potro of Argentina against No. 16 Tommy Robredo of Spain — two men who are a combined 0-6 in Grand Slam quarterfinals. Del Potro beat No. 9 Jo-Wilfried Tsonga of France, 6-1, 6-7 (5), 6-1, 6-4, and Robredo eliminated No. 29 Philipp Kohlschreiber of Germany, 6-4, 5-7, 7-6 (4), 6-2.

Yesterday, when Federer was asked about Nadal, Federer joked: "Um, he didn't retire, right?"

"My dream scenario is to beat Rafa here in the finals," Federer continued, "but I've got to concentrate on my part of the draw and make sure I come through like today."