Swiatek wins first set against Jabeur, ensuring Gauff's passage to WTA Finals semifinals

On a windswept and seemingly endless day of delays at the WTA Finals, the matches still aren't over—but the singles semifinals are set.

When Coco Gauff won her final round-robin match over Marketa Vondrousova earlier Friday, she left Ons Jabeur only one path to the final four at the season-ending championships: a straight-set win.

The Tunisian could still prevail, on this rainy night in Cancun. (Editor's note: she did not.) But even with a 2-1 record, it still wouldn't have been enough to progress.

Here are Saturday's semifinals:

• Jessica Pegula (3-0) vs. Coco Gauff (2-1)
• Iga Swiatek (3-0) vs. Aryna Sabalenka (2-1)

Friday's singles play began with the conclusion of Sabalenka's match against Elena Rybakina. The Belarusian won the first set on Thursday, and wrapped up a 6-2, 3-6, 6-3 victory in the win-or-go-home contest.

Sabalenka can clinch the year-end No. 1 ranking with a win over Swiatek, the only player who could surpass her.

Gauff then eliminated Vondrousova (who finished the tournament 0-3), though not without struggle: 5-7, 7-6 (4), 6-3. She'll face her doubles partner, Pegula, who won all three of her round-robin matches.

Gauff and Pegula are still scheduled to play their final doubles match later tonight.

We will continue to update this developing story.