Unseeded Argentine Mariano Puerta wore down 12th seeded Russian Nikolay Davydenko 6-3 5-7 2-6 6-4 6-4 to reach the French Open final.
Both men were playing in their first Grand Slam semi-final and it turned out to be war of attrition between two of the game's claycourt grinders.
Puerta muscled his way to the first set before Davydenko came back to take the next two with pinpoint hitting.
But Puerta hung on in the fourth then recovered from 4-2 down in the fifth.
"I feel like I am in paradise," the Argentine said after the gruelling encounter which took three hours and 30 minutes to complete.
"I trained so hard for this and put so much in to win this match.
"It was like being back in Buenos Aires with all my supporters in the crowd."
Puerta, who found himself in the tennis wilderness when he was hit with a nine-month doping in 2003, battled his way through the first set after a 90-minute rain delay and looked capable of overpowering the slender Davydenko.
However the Russian, who beat last year's runner-up Guillermo Coria, also from Argentina, in the fourth round, found his range to seize the initiative.
Cutting off the angles with his metronomic double-handed backhand Davydenko moved into a two sets to one lead as the fizz went out of Puerta's game.
But the 26-year-old Argentine found a new lease of life in the fourth set, pouncing for a break in the seventh game to set up a decider.
With both players slugging relentlessly from the baseline it was Puerta who wobbled first, sending a tired-looking forehand over the baseline to trail 4-2.
But Puerta refused to flinch and, summoning all his reserves, surged through the next four games as Davydenko's resistance finally crumbled.