MOSCOW — Anastasija Sevastova reached the Kremlin Cup semifinals by beating Russian veteran Vera Zvonareva 4-6, 7-5, 6-3 on Thursday.

The Latvian player said she was lucky not to lose the match after Zvonareva — once ranked second in the world but in her first tour quarterfinal since 2012 — broke her serve to level the second set at 5-5.

"I started playing better and better and toward the end I was playing one of my best matches here in Moscow," said Sevastova, the highest-ranked player left in the draw at No. 11. Her win ensures she's the first alternate for the WTA Finals.

A U.S. Open semifinalist, Sevastova next faces Tunisian qualifier Ons Jabeur, who upset eighth-seeded Anett Kontaveit 7-5, 6-1.

Jabeur becomes the first Tunisian player to reach a WTA Tour semifinal. She was the 2011 French Open junior champion but has struggled to live up to her early potential.

The other semifinal pits Britain's Johanna Konta against Russian Daria Kasatkina.

Konta went through 6-2, 2-6, 7-6 (2) against Belarusian Aliaksandra Sasnovich as she chases her first title since April 2017.

The sixth-seeded Kasatkina won 6-4, 6-3 against Anastasia Pavlyuchenkova in an all-Russian quarterfinal.

Nick Kyrgios withdrew from the men's tournament with an elbow injury, giving Mirza Basic a walkover to the quarterfinals, where he'll play Karen Khachanov.

Kyrgios said it was a recurrence of a problem which caused him to miss several tournaments around and including the French Open.

"I'm going to choose to wrap up my season, head home and start the recovery," the Australian said. "See you all in 2019."

Second-seeded Daniil Medvedev reached the quarterfinals with a 6-2, 6-1 win over Dusan Lajovic in just 51 minutes. He will next face last year's defeated finalist Ricardas Berankis.

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