PARIS (AFP) - Roger Federer stayed on course for a first French Open title, and a 14th Grand Slam trophy, with a thrilling recovery to beat Argentina's Juan Martin Del Potro on Friday.
The world number two twice came from behind to defeat the towering South American fifth seed 3-6, 7-6 (7/2), 2-6, 6-1, 6-4 in the semi-finals and will now face Roland Garros sensation Robin Soderling in Sunday's final.
Victory there will take Federer level with Pete Sampras's mark of 14 majors and make him only the sixth man to complete a career Grand Slam.
Soderling, the shock conqueror of four-time champion Rafael Nadal, also needed five sets to reach his maiden Grand Slam final with a 6-3, 7-5, 5-7, 4-6, 6-4 victory over Chilean 12th seed Fernando Gonzalez.
Federer, defeated in the last three finals by Nadal, is closing in on his lifetime dream the hard way, having come back from a two-set deficit in the fourth round to beat Tommy Haas.
But he will go into his fourth Roland Garros final buoyed by a 9-0 career record over Soderling, including a straight sets win on the clay of Madrid on the eve of the French Open.
The 27-year-old Swiss star struggled to contain Del Potro in the early exchanges and it wasn't until the fourth set that he was able to carve out his first break on a chilly Paris evening.
"I was under pressure at the start. He had the upper hand at the baseline and deserved to be in the lead. It was important to stay with him and I think my serve got better as the match went on," said Federer.
"I knew I was in with a shot as I had confidence in my physical and mental abilities.
"I think also the conditions helped me. It got slow as the clouds came and became cooler and I knew if I could get the break that things could fall my way."
Federer will not underestimate Soderling in the final.
"Soderling deserves to be there because he also beat Nadal and he was the man to beat in this tournament."
With compatriot and six-time winner Bjorn Borg in support, the 24-year-old Soderling clinched another famous victory, coming back from 1-4 down in the final set against Gonzalez.
Soderling, who had never got beyond the third round in any of his 21 previous majors, is the first Swede to reach the final since coach Magnus Norman in 2000 while Mats Wilander was the country's last champion in 1988.
"At 4-1 down, 15-30 and I double-faulted, I was very tired. But I told myself that it wasn't going to end this way," said Soderling after his three and half hour battle.
"I felt like I could only do my best, that I didn't want to go off the court and feel like I didn't do my best in the fifth set. I just tried harder and all of a sudden it worked again.
"It's a great feeling to be in the final. If you had asked me a couple of years ago which Grand Slam final I'd play in 2009, I wouldn't have said Roland Garros."
Gonzalez, who had been attempting to become the first Chilean in 49 years to reach the final, warned that Soderling will be a real danger in the title match.
"If he plays like he has all week, serving 200kmh on the lines, it's going to be tough for anyone," said the 28-year-old of a man who has also put out 10th seeded Russian Nikolay Davydenko and Spanish 14th seed David Ferrer in his run to the final.
Soderling had breezed through the first two sets before the big-hitting Chilean levelled the semi-final as the Swede, coached by compatriot and 2000 runner-up Magnus Norman, appeared to run out of steam.
The Chilean was quickly 2-0 and then 4-1 ahead in the decider, but Soderling retrieved the break to trail 3-4 and then incredibly broke again to lead 5-4.
He claimed victory with one final, power-packed, deep forehand which left Gonzalez floundering and the Swede on his knees in disbelief at his achievement.
"I had the match in my hands," the Chilean added ruefully.