Rafael Nadal embraced the pain as he set up the chance to win an unprecedented eighth French Open title with an epic victory over Novak Djokovic.
It was another classic match in an era defined by such encounters, with Djokovic and Nadal meeting for the 35th time.
The Spaniard now leads 20-15 and will play compatriot David Ferrer on Sunday, but it could so easily have been Djokovic celebrating a second Roland Garros final in succession.
The match really caught fire in the fourth set as Djokovic recovered from a third-set slump to take it into a decider, twice hit back from a break down.
He then gained an early break in the fifth, and it could have been two, but Nadal showed his remarkable fighting spirit to level at 4-4 and, after four hours and 37 minutes, clinch a 6-4 3-6 6-1 6-7 (3/7) 9-7 victory.
The world number four has been imperious since returning from seven months out with knee problems in February, losing only two matches and winning six titles.
Nadal said: "You need to love the game. When you love the game, you love what you are doing. You appreciate what you are doing in every moment.
"I learned during all my career to enjoy suffering, and these kind of matches are very special. You don't have the chance to play these kind of matches every day.
"So when these kind of matches happen, you suffer, but I really enjoy these moments. I really enjoy suffering, because what's harder is when I was in Majorca last year and I had to watch these kind of matches on the TV."
Nadal served for the match at 6-5 in the fourth set and was two points from victory only for Djokovic to find his best form and level the match in a tie-break.
"Djokovic has special shots at these moments," said Nadal. "His return is amazing. He's able to increase a little bit his level sometimes in these moments, and that puts you in a very tricky situation, and especially if you are against the wind.
"So I knew when I had the break I had a chance, but the match was not over."
Djokovic had made winning the one grand slam title he is missing his main priority for the year, and, when his childhood coach and mentor Jelena Gencic died last weekend, he vowed to try to win it in her memory.
But it was not to be, and a disconsolate Djokovic said: "It's been an unbelievable match to be part of, but all I can feel now is disappointment.
"I congratulate my opponent, because he showed the courage in the right moments and went for his shots, and when he was a break down in the fifth he made some incredible shots from the baseline.
"That's why he's a champion. That's why he's been ruling Roland Garros for many years, and for me it's another year.
"I gave my best. I really did. I really tried to come back. The third set wasn't great at all. I just dropped physically. I managed to come back and start playing really, really well as the match was going on, but it wasn't good enough."
The only slight disappointment was that Djokovic rather fell away in the final game and was broken to love.
The world number one had become increasingly bothered by the state of the court, complaining to umpire Pascal Maria that it was slippery and should be watered and talking to tournament referee Stefan Fransson.
Nadal disagreed so the court was left as it was, and Djokovic said: "I just don't understand. I think that it's wrong what they did."
The two key games of the match came in the fifth set, with Nadal first digging very deep to keep the break to one and hold for 2-3, producing some stunning winners.
And he got his reward when he broke back for 4-4. Djokovic should have had a game point but he overbalanced into the net after hitting a simple put-away.
He protested the point was finished but the ball had not bounced twice so the point went to Nadal.
Djokovic said: "I don't see many wrong things that I've done, especially in the fifth set.
"Who knows which direction it would go if I won that point. And I should have won that point in 99.9% of cases. But this is what happens. It was a bit unfortunate."
Both players were unhappy to be warned for spending too long between points, with Nadal given a point penalty for a second offence, although seeing as he was 5-1 and 40-0 up in the third set at the time, it did not affect the match.
The second semi-final was an anti-climax, with Jo-Wilfried Tsonga, who had hoped to become the first Frenchman in the final for 25 years, outplayed by Ferrer, who won 6-1 7-6 (7/3) 6-2.
It was the Spaniard's sixth grand slam semi-final and the first he has won.