Svetlana Kuznetsova beat an injured Lindsay Davenport to reach the women's final at the US Open.
The American fifth seed showed her experience against the nervous Russian in the first set, breaking three times to win it 6-1 in just 21 minutes.
But Kuznetsova, seeded nine, broke early in the second and, showing greater confidence, levelled the match.
Davenport needed treatment on her left leg but after going 2-0 up, Kuznetsova broke back twice to win 1-6 6-2 6-4.
The 19-year-old is the first Russian to reach the US Open final and she said: "I don't really believe it.
"Lindsay played so well in the first set and I was just trying to hang in there. I will be ready for tomorrow night."
Davenport admitted it was a hard defeat to take after she came into the match on the back of 22 consecutive wins.
"I am disappointed because I had a great opportunity and I was playing so well," said Davenport.
"It is easier to take if I lose because she's playing great. And she was playing great, it is just that I was at a disadvantage.
"I tried to keep the points shorter and go for the bigger shots. I was really playing well and I wanted to continue it."
Davenport's defeat means Frenchwoman Amelie Mauresmo will be the new world number one when the rankings are released on Monday, replacing Justine Henin-Hardenne at the top.
But Davenport hinted that her recent good form means retirement plans may be shelved.
"It would be tough to walk away knowing I can win another Grand Slam," she said.