Third-round action at the Credit One Charleston Open opened with two of the Top 8 seeds falling, with No.15 Amanda Anisimova taking out No.1 Aryna Sabalenka 3-6, 6-4, 6-3 and CoCo Vandeweghe upsetting No.6 Jessica Pegula 6-4, 3-6, 6-4.

Former World No.9 Vandeweghe had lost to Gabriela Lee in the final round of qualifying, but gained entry as a lucky loser following the withdrawal of defending champion Veronika Kudermetova. The 30-year-old sent down nine aces en route to her first Top 20 win since defeating Caroline Garcia in the 2018 Stuttgart semifinals. Anisimova and Vandeweghe will next meet for the first time in an all-American quarterfinal.

Highlights: Vandeweghe d. Pegula

No.4 seed Ons Jabeur was also a belated winner Thursday. The Tunisian had been a game away from victory over wildcard Emma Navarro the previous night before lightning had halted play, and she returned to wrap up a 6-3, 6-2 win by winning four quickfire points over the American.

Though Anisimova's fourth career Top 10 win was an upset on paper, the head-to-head had foreshadowed the result. She had already defeated Sabalenka twice in two meetings, at the Australian Open and Roland Garros in 2019; indeed, the opening set here marked the first time that Sabalenka had taken a set in their rivalry.

Keys to the match: The vagaries of the Sabalenka serve proved crucial, as they have so often in 2022. In the first set, the World No.5 landed 73% of her first serve and won 79% of those points. She fired seven aces and dropped serve only once.

But Anisimova found more of a groove in the second set, coming through a key hold for 3-2 with superb net play and a finely struck forehand winner. Sabalenka, who had only committed three double faults in the first set, coughed up two in a row to lose serve and go down 5-3. Even after Anisimova failed to serve the set out, Sabalenka offered a sixth double fault to go down set point in the subsequent game, and the American took that opportunity.

Anisimova leapt out to a 4-0 lead in the decider as Sabalenka's double fault tally reached 10. Though Sabalenka made a late charge to regain one of the breaks, it wasn't enough; Anisimova served out the win the second time, landing her sixth ace of the day en route.

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