Karolina Muchova saved a match point on Thursday during a dramatic three-set win over the second seed Aryna Sabalenka to reach the final at the French Open for the first time.
The 26-year-old Czech staved off elimination when she was serving with Sabalenka leading 5-2.
Her success forced the Belarusian to serve for a place in Saturday's final.
But she fluffed that chance with three dreadful backhands - one into the net, the second long and the third wide.
But could Muchova profit? She did. Fittingly, a backhand error from Sabalenka gave Muchova the point to bring her back to parity at 5-5.
What happened next in Sabalenka's mind will become standard tennis academy coursework.
At 40-15 up, it went south. Polar. Her fifth and sixth double faults brought Muchova to deuce and a 21st backhand error gave Muchova a break point.
Even a powerful serve betrayed Sabalenka as it provoked an equally scintillating return which she could only shuffle over the net. Muchova ran onto the mid court ball and serenely played her 10th forehand winner of the match down the line to notch up a 6-5 lead.
Chance
But could Muchova profit? Two more backhand errors - the 22nd and 23rd - took Muchova to within two points of her first final at a Grand Slam tournament and a slick drop shot brought three match points.
Sabalenka saved one but it was all over on the next point when a forehand flew wide.
Muchova shook her head and walked calmly up to her opponent to shake her hand before opening up her arms to embrace the acclaim following the 7-6, 6-7, 7-5 victory.
"I tried to keep fighting," she told on-court interviewer Mats Wilander. "And it worked. I don't know what happened."
Sabalenka though will need to find answers rapidly to prevent another traumatic meltdown. The 25-year-old appeared the physically stronger of the pair as the match passed the three hour mark.
Though both were playing in their first French Open semi-final, Sabalenka, as world number two and Australian Open champion, held the advantage in big match experience.
Return
And after losing the first set in a tiebreak, Sabalenka came back from a break down and had to serve at 4-5 and 5-6 down to stay in the match.
Once she had claimed the second set tiebreak, logic and form suggested she would power on. Nearly.
In her first final at a Grand Slam tournament, Muchova will face the defending champion Iga Swiatek who beat the 14th seed 6-2, 7-6.
