Kim Clijsters saw five match points slip away before beating top seed Maria Sharapova in the US Open semi-finals.
The Belgian was on the verge of victory against an out-of-sorts Sharapova when she led by a set and 6-5.
But the Russian recovered from 0-40 and saved two more match points before racing through the tie-break.
Clijsters showed tremendous nerve to stay calm and regain her form, taking the third for a 6-2 6-7 (4-7) 6-3 win and a final against Mary Pierce.
"It was tough," said Clijsters. "I gave everything I had on those match points and she just came up with better shots.
"I said from the third set on 'just go for it'. It worked."
After a nervous start from both players Clijsters surged clear with six straight games.
Sharapova had not been at her best in earlier rounds and had to battle through.
She did well to stay in touch in the second set, but the end looked inevitable when she slipped 0-40 down in game 12.
The Russian was not about to throw in the towel, however, and she came up with a breathtaking drop shot among five saved match points.
She raced through the tie-break but then lost her momentum in the third.
Clijsters' court coverage and relentless power from the baseline took her to 5-2 but, when serving for the match, she again suffered a Sharapova onslaught.
Four magnificent winners cut the deficit but, as so often throughout the tournament, Sharapova could not maintain that level of form.
Clijsters earned two more match points in the following game and this time took the first to move a step closer to a first Grand Slam title.
"I kind of gave it all I had in the tie-breaker," said Sharapova. "In the third, I kind of ran out of gas.
"At that point it's pretty tough because physically I still have to get a lot better and I have to play these three-setters. The points are going to go on and on and on.
"This is not something that's going to happen overnight. I'm only 18 and this is going to take time.
"My body is still growing and I'm still adjusting to my own body."