WTA final: Coco Gauff beats Iga Swiatek and reaches the semi-finals

In Tuesday's earlier match, Wimbledon champion Krejcikova faced little challenge from an underperforming Pegula, who reached the final of the tournament last year.

In a performance devoid of positive energy, Pegula struggled to cope with the Czech's huge serves, including 11 aces, and scored just four winners in a game that lasted little more than an hour.

The 30-year-old US Open finalist Pegula got off to the perfect start with a love hold in her first service game, amid a series of unforced errors from Krejcikova.

But after Krejcikova got the first break midway through the first set, sixth seed Pegula's body language began to sour and she gave her opponent the first lead with a sloppy return that was fired into the net from close range.

At the start of the second set, Pegula's form did not improve as Krejcikova broke her serve at the first opportunity, although there was a brief reprieve for the American as she equalized in the next game.

But any glimmer of hope of a Pegula comeback was extinguished when she double-faulted to give her opponent the break back, after which Krejcikova – whose performance was anything but brilliant – cruised to a comfortable victory with a single break point as the only hurdle.

“I'm really happy with the way I played today. I felt like I had to play my best tennis,” said the eighth-seeded Krejcikova, who is ranked 13th in the world but qualified for the WTA Finals by virtue of her Grand Slam tournament in 2024 .

“I had some very good moments this season, especially winning the Wimbledon title. It was truly indescribable and to be here now is a great privilege, playing in the last eight.”

The WTA Finals will be held in Saudi Arabia for the first time – a move that has been criticized by some because of the human rights situation in the country.

This year's tournament has record prize money, with the individual winner expected to pocket around £4 million.

In the final purple group round-robin matches on Wednesday, Sabalenka will face Rybakina before Jasmine Paolini and Zheng Qinwen face off for a place in the semi-finals.