Serena Wiliams will have to wait for a record-breaking 23rd grand slam title after the American endured a shock US Open defeat to Karolina Pliskova.
Williams stood two victories away from beating Steffi Graf’s Open-era best 22 major triumphs but her charge was ended in stunning fashion by Pliskova, who who won 6-2 7-6 (7/5).
The disappointment is doubled for Williams as it means she will also surrender the world number one ranking at the end of the tournament to Germany’s Angelique Kerber.
Pliskova will now face either Kerber or Denmark’s Caroline Wozniacki in her first grand slam final on Saturday.
The world number 11 had never gone past the third round of a major tournament before but she simply outplayed Williams at her own game, with power, aggression and a blistering serve.
“I don’t believe it,” Pliskova said on court afterwards. “Actually I do believe it. I always knew I had a chance to beat anyone if I play my game.
“It is amazing to be in the US Open final and to beat Serena because she is a champion.
“Even down a set and a break, she is still fighting but I’m just really happy I stayed there and got the win.”
It is the second year running Williams has lost here in the semis and the 34-year-old, who turns 35 later this month, was hobbling in the second set.
After the match, she revealed she had been nursing a problem with her left knee in New York since round two.
“Yeah, I have been having some serious left knee problems,” Williams said.
“I wasn’t able to move the way I wanted to move. When you’re injured you’re thinking of other things when you should be just playing and thinking of your shots.
“My mind was just a little bit everywhere. But it was what it was.”