PARIS — Sentimental favorite Roger Federer did not quite follow the script Friday at the French Open. He decided to go for high drama.

Striving to complete a career Grand Slam, Federer came from behind twice in the semifinals to beat big-serving Juan Martin del Potro 3-6, 7-6 (2), 2-6, 6-1, 6-4.

Playing in his fourth consecutive Roland Garros final, Federer will try for his 14th major title to match Pete Sampras' record.

"There's still one more step," Federer said. "I was a bit lucky but I fought well. Juan Martin was playing really well."

Federer's opponent Sunday will be No. 23-seeded Robin Soderling of Sweden, who extended his improbable Roland Garros run by beating No. 12 Fernando Gonzalez in another seesaw semifinal, 6-3, 7-5, 5-7, 4-6, 6-4.

With nemesis Rafael Nadal eliminated in the fourth round, Federer faces a less daunting path to that elusive Roland Garros championship. He's 9-0 against Soderling.

But then Federer had swept his previous five matches and 12 sets against del Potro. The 6-foot-6 Argentine rose to the occasion in his first major semifinal and kept on the offensive for much of the match, but began to tire in the fourth set.

Federer broke for the first time 2½ hours into the match to lead 3-1. Del Potro lost his next two service games as well, allowing Federer to sweep seven games in a row and finally take the lead.

By then, Federer was in top form, gliding across the clay that has vexed him in the past. He won a frantic rally and a standing ovation by lunging to slice a forehand into the open court for a 3-1 lead in the fifth set. There were more highlight-reel shots down the stretch, and he closed the victory with forehand winners on back-to-back points.

In the all-Russian women's final Saturday, top-ranked Dinara Safina will try for her first Grand Slam title against Svetlana Kuznetsova.

Federer trailed for much of the semifinal, struggling to hold serve and unable to break. Sensing his once-a-year opportunity again slipping away, he slapped himself in the face after losing one frantic rally.

Maybe that helped. And maybe he was buoyed by a crowd that kept chanting "Ro-ger! Ro-ger."

Del Potro made one last charge in the final set, hitting several ferocious shots to break for 3-all. But he missed all eight first serves in the next game and finally dumped a weary second serve into the net on break point.

On a cool, cloudy, evening, Federer looked out of sorts early, failing to convert two early break points and losing serve at 2-all. He twice fell behind love-40 while serving and shanked an easy overhead, perhaps a sign of nerves.

Federer served better in the second set but was broken when he played a sloppy game to start the third set and again found himself trailing a bigger, younger, more powerful opponent.

One point-blank exchange forced Federer to retrieve three del Potro volleys, and he failed to reach a fourth. Federer hung his head, and as he walked back to the baseline he slapped himself.

A game later, del Potro closed the third set, before Federer mounted his latest comeback. He overcame a two-set deficit to beat Tommy Haas in the fourth round.

Next up: Soderling. He scrambled the draw with his win Sunday over the four-time defending champion. Federer has been beaten at the French Open each of the past four years by Nadal, the past three times in the final.

The Swede is beyond the third round for the first time in 22 career major tournaments, and he'll play in his first clay-court tournament final.

"He deserves it," Federer said. He's still the one who beat Rafa, who was the man to beat in this tournament."

Against Gonzalez, Soderling let a big lead slip away when he lost his serve in the final game of the third and fourth sets. He fell behind 3-love and 4-1 in the final set, but down the stretch came up with the kind of shotmaking that has carried him through the tournament, and he swept the last five games.

"I had maybe the biggest challenge in tennis right now to beat Nadal here on clay in Paris," he said. "I was still in the tournament, so even though I played a great match, I wanted more. I still feel that way."

The victory over Gonzalez was only his fourth in a five-set match.

"I did a good job of coming back," Gonzalez said. "But Soderling is playing at a really high level. He gets to every ball. I couldn't take him out of position."

The first semifinal had lots of drama, and a little controversy. Gonzalez challenged a call late in the fourth set, contending a shot by Soderling had landed wide, and when the umpire denied his appeal, Gonzalez sat on the disputed mark in the clay to smooth it out.

"I did something for fun," Gonzalez said. "One point doesn't affect a five-set match."

Gonzalez won the game anyway, but played the rest of the match with dirt caked on his shorts.

The quality of play was high throughout. Soderling had 74 winners, including 16 aces, and Gonzalez totaled 59 winners, including 22 aces.

When Soderling hit a forehand winner on the first match point, he fell to his knees and covered his eyes.

"My first feeling was actually relief that the match was over, because it was a really long match, and I was tired at the end," Soderling said. "And then after a few seconds, I got really, really happy."

He has won nine consecutive matches, a career best, and is expected to climb to a career-high ranking of No. 12 next week.