PARIS - There have been times this year when Roger Federer's cloak of infallibility slid from his shoulders, when his absolute dominance against anyone but Rafael Nadal and at any tournament but the French Open was not quite so absolute.

Federer arrived at Roland Garros with one title, his lowest count since 2001. He arrived with seven losses, more than his total for any of the previous three entire seasons.

And so it was yesterday that for the first set of his French Open quarterfinal against 24th-seeded Fernando Gonzalez, Federer looked, well, human. His serve was broken three times. He shanked shots. He was, by his own admission, "a little bit rattled."

Still, as he's done so many times, Federer adjusted and regrouped, beating Gonzalez, 2-6, 6-2, 6-3, 6-4, to extend his own record by reaching a 16th consecutive Grand Slam semifinal. Federer moved two wins away from completing a career Slam and earning his 13th major championship, which would leave him one shy of Pete Sampras' mark.

"At one stage, I was a bit afraid," the No. 1-ranked Federer said, "because the match was not going the way I wanted."

In addition to his opening-set lapse, Federer fell behind by love-40 while serving to begin the third. Given a chance to pull ahead again, Gonzalez missed two relatively easy shots before Federer won a 13-stroke exchange to account for the third break point. Thus began this amazing stretch: Federer won 36 of the last 40 points on his serve, including each of the final 17.

"It wasn't the same Federer as the first set," said Gonzalez, who fell to 1-11 against the Swiss star, including a loss in the 2007 Australian Open final.

Impressive as it was, Federer's turnaround had nothing on the one fashioned by No. 13-seeded Dinara Safina in the women's quarterfinals. The younger sister of two-time major champion Marat Safin trailed No. 7 Elena Dementieva by a set and was down, 5-2, in the second, then was one point from losing at 5-3, before coming all the way back to win, 4-6, 7-6 (5), 6-0.

The deficit was identical to the one faced by Safina a round earlier, when she trailed by a set and 5-2 in the second and erased a match point at 5-3 en route to upsetting No. 1 Maria Sharapova.

"Once you went through this," Safina said, "you always believe: 'Why not the second time?' "

Safina's semifinal today will be an all-Russian matchup against No. 4 Svetlana Kuznetsova, the 2004 U.S. Open champion and 2006 French Open runner-up. No. 2 Ana Ivanovic and No. 3 Jelena Jankovic will meet in an all-Serbian semifinal.

Kuznetsova, who defeated Kaia Kanepi of Estonia, 7-5, 6-2, took note of Safina's last two performances.

"She has too many lives," Kuznetsova said, "so I have to be careful."

Safina handed Dementieva a match point at 5-3 in the second set by double-faulting to 30-40.

"I just choked so badly," Safina said.

Dementieva repaid the favor, though, by flubbing a backhand return. Later in that set, Safina wasted five set points - three at 6-5, two in the tiebreaker - before finally converting on her sixth with a backhand winner that caught the baseline.

The final set was no contest, allowing Safina to reach her first major semifinal.

"You can say that it's a breakthrough," she said.

Federer's semifinal streak includes four straight in France, but he lost at that stage in 2005 and in the finals in 2006 and 2007 - each time against Nadal.

"To make four in a row is a great accomplishment, but this year I'm obviously particularly aiming for the title," said Federer, who recently enlisted the help of Jose Higueras, past coach of French Open champions Michael Chang and Jim Courier. "So I hope it's not going to stop here."

Federer faces 59th-ranked Gael Monfils tomorrow. The 21-year-old Frenchman is the lowest-ranked semifinalist in Paris since 1999. It is Monfils' first Grand Slam semifinal.

"I'm at home," Monfils said after delighting local fans by knocking off No. 5 David Ferrer, 6-3, 3-6, 6-3, 6-1. "I'm ready and waiting for him."

In tomorrow's other match, three-time defending champion Nadal will take a 26-0 record at the French Open into his showdown with No. 3 Novak Djokovic, the Australian Open winner.