Amanda Anisimova rallies past Iga Swiatek at WTA Finals

Amanda Anisimova rallied for a 6-7 (3), 6-4, 6-2 victory over Iga Swiatek of Poland on Wednesday to reach the semifinals of the WTA Finals in Riyadh, Saudi Arabia.

The fourth-seeded Anisimova advanced to face No. 6 seed Elena Rybakina of Kazakhstan, who beat Russia's Ekaterina Alexandrova 6-4, 6-4 to complete her sweep of round-robin matches in the Serena Williams Group.

Anisimova needed two hours and 36 minutes -- the longest match of the week -- to complete her comeback against Swiatek in their winner-take-all clash. The American saved all four break points and broke Swiatek's serve in the final games of the second and third sets.

Anisimova finished with a slight 107-103 edge in total points in the hard-fought match. Swiatek lost back-to-back matches after winning the opening set for the first time in her career.

"Honestly, I did everything I could today, so like no regrets," Swiatek said. "I felt like I was really in the zone, positive mindset. I fought and really didn't give up -- it wasn't enough, which makes me sad."

With the victory against World No. 2 Swiatek, Anisimova became the only player this year to register wins over the current top three players: No. 1 Aryna Sabalenka and No. 3 Coco Gauff.

Rybakina, who had already clinched her spot in the semifinals, needed only 73 minutes to finish off Alexandrova.

"Every match I play, I want to win," Rybakina said after the win. "Each win gives you confidence, so I'm really happy with that for now. The last few matches have been great and hopefully I can continue that."

Rybakina served eight aces, saved five of six break points and converted three of four break chances to extend her overall winning streak to nine matches, coming off a championship last weekend at China's Ningbo Open.

Rybakina had been scheduled to face Madison Keys, who withdrew hours before the match due to a viral illness.

"Really disappointed to not be feeling my best and ultimately having to withdraw from the tournament," Keys said in a statement. "Huge accomplishment to make it this far and very proud of myself for doing that and having a great year. I hope to be back next year."

Action continues Thursday in the Stefanie Graf Group, with No. 1 seed Sabalenka facing No. 3 Gauff and No. 5 Jessica Pegula taking on No. 8 Jasmine Paolini. Paolini (0-2) is the only group member who has already been eliminated. Sabalenka is 2-0 and Gauff and Pegula are both 1-1.