Gaston Gaudio destroyed fellow Argentine David Nalbandian 6-3 7-6 (7/5) 6-0 to book a place in the French Open final.
Nalbandian was playing in his third Grand Slam semi-final, but he was outfought by the unseeded Gaudio.
After clinching a tight first set, the match turned decisively in Gaudio's favour when Nalbandian blew a 5-1 lead and two set points in the second.
Gaudio took it on a tiebreak before Nalbandian fell apart in the third set.
"I never thought I was going to be in the final of such a big tournament like this," said Gaudio, who broke down in tears after clinching match point.
"I was thinking about all the effort I made when I was young and all the dreams about winning here so that is why I was a little emotional at the end."
Gaudio is the first Argentine to reach the men's final at Roland Garros since Guillermo Vilas in 1982.
However, he could face another compatriot in Sunday's final, with third seed Guillermo Coria facing Britain's Tim Henman in the other semi-final.
Nalbandian said he had been hampered by a stomach injury, which particularly affected his serve.
"I had a problem with my intercostal muscles in the last set against Kuerten, in the quarter-final," he said.
"It was a little better today but it was a still a bit of problem. But I had my chances in the second set and I didn't take them. Then he played very well in the third set."
Nalbandian was angered by a moment of controversy during the crucial second-set tiebreak.
Leading 5-2, Gaudio served from the wrong side of the court and won the point, giving him four set points.
Nalbandian pointed out the mistake to the umpire and spoke to the tournament referee after Gaudio had taken the set but to no avail.
"The umpire should have been concentrating more on his job," said Nalbandian.
"I don't know if he can be sanctioned but it was a bad mistake."