US Open: Serena Williams stunned in semi-final loss as Karolina Pliskova sets up final against No 1 Angelique Kerber

Williams suffered a second consecutive US Open semi-final exit after losing 6-2, 7-5, meaning Pliskova will face new world No 1 Kerber in the women's final

Serena Williams suffered a 6-2, 7-5 defeat by Karolina Pliskova in the US Open semi-finals (Getty)

There has long been talk of a changing of the guard at the top of tennis and in the women’s game at least it is finally about to happen. After an unbroken run of more than three years at the top of the world rankings, Serena Williams will be toppled by Angelique Kerber on Monday after suffering another remarkable semi-final defeat here at the US Open.

Twelve months ago it was Italy’s Roberta Vinci who ended Williams’ hopes of claiming a seventh title at Flushing Meadows. This time it was the Czech Republic’s Karolina Pliskova who halted the 34-year-old American in her tracks, winning 6-2, 7-5 to set up a final showdown on Saturday with Kerber, who beat Caroline Wozniacki 6-4, 6-3 in the other semi-final.

For Williams it was a case of déjà vu. For two years in a row she has faced an underdog in the semi-finals of her home Grand Slam event knowing that she was on the verge of creating history.

Last year Vinci, the world No 43, ended Williams’ hopes of becoming only the fourth woman in history to complete a pure calendar-year Grand Slam following her triumphs at Wimbledon and the Australian and French Opens.

This time Williams faced a higher-ranked player in Pliskova, though the world No 11 had arrived at the tournament as the only top 20 player who had never gone beyond the third round of a Grand Slam event. She will climb to No 6 in next week’s updated world ranking list or to No 5 if she wins the title.

Williams would have broken Steffi Graf’s Open era record of 22 Grand Slam singles titles by winning the tournament here. Her defeat also ended her hopes of beating Graf’s record of 186 consecutive weeks at the top of the world rankings, which she had equalled this week. How appropriate it will be that she is replaced by Kerber, another German and a player who grew up with Graf as her idol. At 28 Kerber will be the oldest player ever to top the rankings for the first time.

Although Pliskova played superbly and kept her nerve throughout, Williams was suffering from an injury which she had sustained earlier in the tournament. At the start of the fortnight she had been concerned by a shoulder injury which had forced her to withdraw from her previous tournament, but she revealed after her defeat to Pliskova that she had also been dealing with what she described as “serious left knee problems”.

Although Williams declined to go into any details about the injury, she explained: “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.”

Pliskova has one of the best serves in the women’s game – she has hit more aces (446 from 55 matches) on the women’s tour this year than any other player – and conceded only six points on her first serve in the whole match. At 109mph her average first-serve speed was 1mph faster than Williams’.

However, there was much more to Pliskova’s game than a powerful serve. She moved smoothly around the court, timed her ground strokes beautifully and played a smart game, almost invariably choosing the right shot at the right time.

When the pressure was on, Pliskova held her nerve. Having taken the first set with something to spare, she regrouped in the second set after dropping her serve to love immediately after breaking in the fifth game. Williams, who had only one break point in the match, fought back from 3-0 down in the tie-break to lead 4-3, but double-faulted on the next point and again on match point.

“Karolina played great,” Williams said afterwards. “I think if she had played any less then maybe I would have had a chance. I wasn’t at 100 per cent, but I also think she played well. She deserved to win.”

In the fourth round Pliskova beat Williams’ sister, Venus, after saving a match point. “You can’t do much better than to beat both sisters in one tournament in New York,” Pliskova said. “For me it’s really something special. Obviously the match with Venus helped me, not only with the game, but also with the crowd as well. That was my first match on centre court.”

While Grand Slam success had been elusive for Pliskova until this tournament, her talent has been recognised since her junior days, when she claimed the Australian Open girls’ title by beating Laura Robson in the 2010 final. She has won six titles on the main women’s tour and is currently on an 11-match unbeaten run, having arrived here after winning the tournament in Cincinnati.

Her big serve makes Pliskova a particular threat on grass. She won the title in Nottingham this summer and finished runner-up to Dominika Cibulkova at Eastbourne - having beaten Johanna Konta in the semi-finals - before suffering a disappointing second-round defeat to Misaki Doi at Wimbledon.

Pliskova won the Cincinnati title with a crushing 6-3, 6-1 victory in the final over Kerber, who would have taken the No 1 spot then if she had won the tournament. Kerber has won four of her seven career meetings with the Czech, including their matches last year at Edgbaston and Stanford.

Kerber, who beat Williams in the Australian Open final this year and lost to her in the Wimbledon final two months ago, never looked in danger of losing to Wozniacki after winning the first four games. The German has won more main draw matches this year (53) than any other player on the women’s tour.

“When I was really young I was always dreaming of being world No 1,” Kerber said. “I remember the match in Cincinnati, where I had the chance to reach No 1 with the win there. After that I told myself: ‘OK, I will get one more chance.’ Now I have the world No 1 ranking. It’s something really special.”