Unseeded Karolina Muchova saved a match point before battling past second seed Aryna Sabalenka 7-6(5) 6-7(5) 7-5 on Thursday to reach the French Open final and end the Belarusian's dream of becoming world number one.
Australian Open champion Sabalenka would have taken over the top spot in the rankings by winning the title in Paris but she failed to convert her chance at 5-2 in the third set and bowed out to the gifted Czech, who cleverly defused her opponent's power game and took the last five games in a row.
The last unseeded player left in the men's and women's draw, Muchova did not attempt to match Sabalenka's massive hitting power from the baseline.
Instead the Czech, who battled back from the mid-200s into the top 50 after an injury in 2021, opted for a lighter touch.
She sliced the ball to take the pace off, playing Sabalenka's backhand and hitting drop shots to force the tall Belarusian into the net.
Sabalenka, the biggest hitter in the women's game, could not use her fierce forehand at will and was clearly rattled.
She was broken as Muchova moved 5-4 up but the Czech wasted one set point on her serve and was broken straight back before bagging the set at the second opportunity in the tiebreak.
The Belarusian, who had caused a furore in the tournament after her initial refusal to comment on Russia's invasion of Ukraine and her country's role as a staging ground for Russian troops, was broken at the start of the second.
The pair traded two breaks each in the second set before Sabalenka earned two set points in the tiebreak.
She squandered the first with a double fault but showed no nerves on the next to level.
Sabalenka wasted four break points at 1-0 but snatched the key break in the third to move 4-2 clear.
After Muchova had saved a match point at 5-2 down she launched her own comeback to win five straight games and reach her first Grand Slam final.