Serena Williams overcame a shaky opening set on Thursday to rally past her sister, Venus Williams, 3-6, 6-3, 6-4 and reach the quarterfinals at The Top Seed Open in Lexington, Ky.

Serena Williams, the top seed in the event, improved to 19-12 in the all-time series between the sisters, winning the first meeting since the third round of the 2018 U.S. Open.

She got off to a hot start by breaking Venus' serve in the game's opening set, but Venus responded with consecutive breaks of Serena and cruised to take the first set.

After Serena converted one break point to take the second set, she again blew a lead in the third, but this time responded calmly. Trailing 4-2, she broke Venus' service twice in a row and then served out for the victory.

"I'm super relaxed," Serena Williams said afterward. "Having no crowd sort of makes things more relaxing."

"I've practiced in louder places than this court," she added with a laugh.

The only other seeded player in action lost, as Switzerland's Jil Teichmann made quick work of fifth-seeded Yulia Putintseva of Kazakhstan in a 6-2, 6-2 victory.

In the day's other two matches, Shelby Rogers downed Leylah Fernandez of Canada 6-2, 7-5, and Catherine Bellis dispatched fellow American Jessica Pegula 6-3, 6-2. Rogers will face Williams on Friday.

Prague Open

Top-seeded Simona Halep of Romania recovered from a slow start to rally for a 3-6, 7-5, 6-2 victory over Barbora Krejcikova of the Czech Republic to reach the quarterfinals.

Both struggled mightily with their serves, combining for 16 breaks of service (with Halep converting nine of 14 chances) and 13 double faults, including 10 by Halep. The former world No. 1 -- currently ranked No. 2 -- Halep dropped four set points on her own serve in the second set before winning it three games later. She then came from a break down in the final set with three straight breaks of Krejcikova's serve to finish the match.

Halep will next face Magdalena Frech of Poland, who survived Dutchwoman Arantxa Rus 6-3, 2-6, 6-4. In other action, Spain's Sara Sorribes Tormo cruised by Germany's Laura Siegemund 6-2, 6-3 and Canada's Eugenie Bouchard outlasted Slovenia's Tamara Zidansek 7-6 (2), 6-7 (2), 6-2.