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 on Friday that was halted on Thursday due to stormy weather in Cancun.
Under bright sunshine but still unrelenting winds, world number one 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 other group, all four players - Iga Swiatek, Ons Jabeur, Coco Gauff and Marketa Vondrousova - are still in contention for the semis and due to play later on Friday.