PARIS -- Awful at the start, masterful enough later to produce shots that must be seen to be believed, Roger Federer leaned back in his sideline seat and exhaled.
His opponent Friday had just quit with an injury, and a smile slowly crept across Federer's face as he realized that a berth in his first French Open final was secured, a fourth consecutive Grand Slam title now merely one victory away.
Ah, but what a victory that will have to be: No. 1 Federer now faces No. 2 Rafael Nadal, the defending champion, winner of 59 straight matches on clay and owner of a 5-1 career mark against the Swiss star.
Each of the previous three years, one of the French Open finalists was unseeded. Now fans will be treated to the tournament's first final between men seeded 1-2 since 1984, and so much else is at stake for Federer on Sunday. He's trying to become only the third man in tennis history to win four majors in a row, the first since Rod Laver in 1969. He also can become the sixth man to collect a career Grand Slam.
"Quarters, semis -- it's all nice and stuff," Federer said, "but you want to go out there on the Sunday."
And he usually does. He's reached the final at his last 14 tournaments, the longest such streak since Ivan Lendl's 18 in a row in 1981-82. The last time Federer failed to make it to a final? When he lost to Nadal in the 2005 French Open semifinals.
"Federer is a superstar," Nadal said. "If I don't play at 100 percent, I'm going to lose, for sure."
Against No. 3 David Nalbandian on Friday, Federer went from stunningly bad to as good as he gets, and was leading 3-6, 6-4, 5-2 when the Argentine stopped because of a strained abdominal muscle.
Spectators who paid good euros for their tickets might have been upset to be witness to the first French Open men's semifinal to end in retirement, the record ninth of the tournament. Then again, they did get to watch an hour of magic from Federer, plus more than 21/2 hours of Nadal in all of his scrambling, leaping, fist-pumping glory in the day's second match, a 6-4, 6-2, 7-6 (7) victory over No. 4 Ivan Ljubicic.
Nadal handled Ljubicic's booming serve with nary a problem and overcame the one tense moment, down 5-3 in the tiebreaker, with the help of two aces of his own. Nadal also conjured up several crisp passing shots on the fly, including one forehand he celebrated by scampering the width of the court before thrusting a leaping uppercut.
After Ljubicic missed a volley to end it, Nadal put his racket down, then went to the middle of the court and dropped to his knees, raising his arms.
"Maybe the final of Grand Slam always is exciting, no?" Nadal said.
No such joyous display for Federer after his semifinal's odd denouement. Then again, Federer generally doesn't emote much, and he never betrayed a shred of anger or angst during his disastrous first 39 minutes against Nalbandian.
Falling behind by a set and 3-0, Federer whiffed on a service return, clanked shots off his racket frame, sent groundstrokes long or wide by several feet, even shanked a ball into the stands.
"It was important for him to figure out what was going on and turn things around," said Federer's coach, 1966 French Open champion Tony Roche. "There's tremendous pressure on him ... but, so far, he's shown he's capable of handling it."
Federer blamed his woes on the swirling wind that rippled the players' shirts, and he credited Nalbandian, too, for playing well.
Suddenly, Federer's touch was back. In the second set's fourth game, Nalbandian ripped a backhand down the line, and Federer reached down -- his racket striking the clay -- to chop a forehand winner. Shocked, Nalbandian watched the ball sail past, his feet rooted to the ground.
Federer finally mustered his first break point in the next game, when Nalbandian said his injury flared up, and a double-fault made it 3-2.
Two games later came the shot of the tournament. With Federer forward, Nalbandian lofted a lob to the corner. Federer spun and chugged after the ball, his back to the net. At the last instant, he wheeled back all the way around to face the court, somehow got his body out of the way, and flicked a forehand winner.
Federer held up his left index finger, as if to remind everyone who's No. 1, while fans saluted the flourish with a standing ovation.
"I couldn't play it between the legs, so I had to turn again. Then I thought, 'What do I do now?"' Federer explained. "That was a piece of good luck."
Nalbandian's take on the trick shot: "Incredible," he said, shaking his head.
That was part of 15 minutes of brilliance by Federer, in which he won 20 of 27 points. Federer broke to start the third set, and Nalbandian was treated by a trainer at the next two changeovers.
"I didn't feel like I can continue playing for three, four hours. Doesn't matter the score," said Nalbandian, hurt during his quarterfinal. "I'm going to fight if I'm OK. If I'm not OK, I mean, fight against what? It's impossible."
Nalbandian's first retirement in 299 career singles matches made Federer 44-0 this season against anyone not named Nadal.
The Spaniard, who turned 20 last week, has won all three times they've played in 2006, including at May's Rome Masters, when Federer blew two match points, then accused Nadal's uncle and coach, Toni, of improperly providing help during the final.
Ljubicic complained that Nadal was taking too much time between points, and chair umpire Carlos Ramos issued a warning.
After the match, Toni Nadal said Ramos was "hurrying Rafa" and has "a horrible attitude."