Serena Williams’ 186-week reign as world No.1 is over while the women to replace her at the top, Angelique Kerber, is through to the US Open final.
Williams lost her semi-final to Karolina Pliskova 6-2 7-6 (7-5) on Thursday night at Flushing Meadows to relinquish the top rank she’d held since February 2013.
The 10th-seeded Czech moved into her first grand slam final, where she’ll meet Kerber, who later accounted for Caroline Wozniacki 6-4 6-3.
With the defeat, Williams’ bid to break the professional era record for career grand slam titles also came to a halt.
For Williams, whose 22 grand slam titles has her tied with Steffi Graf, it marked the second consecutive year she lost in the semis while chasing history.
Williams came into last year’s semi-finals as the three-time defending champion and two wins shy of a rare calendar-year grand slam but was upset by Roberta Vinci.
She clutched at her left hamstring occasionally in the second set and double-faulted to end it.
“I don’t believe it. Actually, I do believe it,” Pliskova said.
“I always knew I have a chance to beat anybody if I’m playing my game.
“But this is something amazing.
“Serena, she’s a champion so it’s never easy to play her. You saw even when she was down a break she’s still fighting so it’s very hard.”
But a clearly annoyed Williams refused to use fatigue as an excuse for her loss and instead blamed her sluggishness more on left knee problems that limited her mobility.
“OK, I’m not going to repeat myself. I wasn’t tired from yesterday’s match,” said Williams. “If I can’t turn around after 24 hours and play again then I shouldn’t be on tour.
“I have been having some serious left knee problems. I wasn’t tired. Fatigue had absolutely nothing to do with it.
“I wasn’t able to move the way I wanted to move.”
With the victory Pliskova completed a Williams family double having also beaten Serena’s older sister, sixth-seeded Venus, in the fourth round.
The title decider between Kerber and Pliskova on Saturday will be a rematch of the final at Cincinnati nearly three weeks ago.
Kerber would have taken over the No.1 ranking then had she won that day, but Pliskova instead captured a breakthrough title and has ridden that momentum since.
Kerber had never made a grand slam final at the start of this year.
Then she not only advanced that far but won the title at the Australian Open, beating Williams in the championship match. She followed that up with a run to the Wimbledon final, where she lost to Williams.