Aryna Sabalenka outlasted Elena Rybakina 6-2 3-6 6-3 to reach the WTA Finals last four in a win-or-bust group match that was halted overnight due to stormy weather in Cancun.
Under bright sunshine but still unrelenting winds, world No.1 Sabalenka unleashed an ace out wide on match point to send fourth-seed Rybakina packing from the year-end tournament.
"I didn't really think a lot about this match," Sabalenka told Tennis Channel. "I was just like, whatever. I'm going to go out there and do everything I can and if I win, I win and if I lose, I go home on vacation," she said with a laugh.
"I was just trying to play as good as I can."
Belarusian Sabalenka joins American group winner Jessica Pegula in the semi-finals of the event between the world's top-eight players. Kazakhstan's Rybakina and eighth-seeded Greek Maria Sakkari were eliminated from the group stage.
In the first match of the other four-player group, Coco Gauff came from a set and 5-6 down to eliminate Marketa Vondrousova and reach the doorstep of the semis.
The US Open champion shook off her dispiriting straight-sets loss to Iga Swiatek on Wednesday and showed great heart to turn the tables on Wimbledon champion Vondrousova amid pauses in play due to rain and swirling winds.
With the Czech serving for the match, the American teenager dug deep, walloping a forehand at the net to break serve and send the second set to a tiebreak that she won with conviction.
In the decider Gauff, seeded third, broke Vondrousova at love for a 3-2 lead she would not relinquish, pumping her fist and letting out a scream when her opponent's forehand sailed long on match point.
As a result of that match, Swiatek, who plays Ons Jabeur in the final match of the night, advances to the semis.
The Tunisian Jabeur would need to beat the second-seeded Pole in straight sets to advance in the group and deny Gauff a place in the semis.
Earlier, the Women's Tennis Association conceded the Finals in Cancun was "not a perfect event" and signalled changes after a series of complaints from top players about how they were treated.
In a letter to the players, leaked to Sports Illustrated, WTA chief Steve Simon said the late selection of the Mexican resort to host the WTA's showpiece end-of-season tournament was "based on a number of complicated factors".
"It is clear you are not happy with the decision to be here in Cancun. I understand that and you have been heard," he wrote after thanking the players for attending a meeting in Cancun.
"It is not a perfect event, we understand the conditions are a challenge and the WTA accepts responsibility for that."
World No.1 Sabalenka had blasted the WTA over the court conditions after the opening day of group play and said she felt "disrespected" by the standard of organisation at the prestigious event.
with AP