Charleston: American Amanda Anisimova rallied after losing the opening set to beat top-seeded Aryna Sabalenka of Belarus 3-6, 6-4, 6-3 on Thursday and reach the quarterfinals of the Charleston Open.
In more surprises, Ekaterina Alexandrova of Russia and CoCo Vandeweghe of the United States both reached the final eight with wins over seeded opponents.
Alexandrova defeated No. 3 seed Karolina Pliskova of the Czech Republic 6-3, 6-1 while Vandeweghe topped countrywoman and sixth-seeded Jessica Pegula 6-4, 3-6, 6-4.
Spain's Paula Badosa, the second seed, dropped her first set before fighting off American Claire Liu for a 3-6, 7-6 (8), 6-1 victory to move into the quarters.
No. 10 seed Belinda Bencic of Switzerland, the Olympic gold medalist last summer, defeated ninth-seeded Madison Keys of the United States 6-4, 6-4.
Fourth-seeded Ons Jabeur did double duty, winning twice on Thursday to make the quarters. Jabeur's match with Emma Navarro was halted Wednesday because of severe weather with her leading 6-3, 5-2. The two returned Thursday where Jabeur won four straight points to close things out.
Later, Jabeur eliminated Irina-Camelia Begu of Romania 6-3, 6-2.
Magda Linette of Poland had it worse than Ons. Linette, whose Wednesday match was also washed out, beat seventh-seeded Lynette Fernandez of Canada 3-6, 6-3, 6-4 in the afternoon. Linette returned at night to top Kaia Kanepi of Estonia 6-3, 4-6, 6-2.
In all, Linette played 55 games in four hours, 38 minutes and 16 seconds of winning tennis to advance.
Jabeur said Begu found some rhythm in the middle of the match. "But I'm glad that I really won my serve at the end," Jabeur said.
Sabalenka had won her first match in nearly six weeks here Wednesday and took the opening set without too much of a struggle. But Anisimova, 20, who is ranked 47th in the world found her rhythm after the break as Sabalenka began to make mistakes.
Sabalenka had two straight double faults to trail 5-3 and Anisimova was able to serve out the set.
Anisimova continued her run in the deciding set, breaking Sabalenka's serve twice for a 4-0 lead. Sabalenka closed to 5-4, but Anisimova closed out the match with her sixth ace and improved to 3-0 against the world's fifth-ranked player.
Anisimova was thrilled with her third match victory in as many days. She'll face Vandeweghe on Friday to reach the semifinals.
Badosa also got off to a bad start against the 21-year-old Liu. Badosa was up 5-3 in the second set when Liu won three of the last four games to set up the tie breaker. Liu was two points away from winning the match four times in the tiebreak, yet Badosa turned away each challenge.
Badosa converted her fourth set point off a backhand winner to close the set, which lasted 72 minutes. Badosa gained control after that in the third set to advance.
In the quarterfinals, she'll take on Bencic, who overcame a nearly two-hour rain delay after winning the opening set against Keys. After the rain stopped the court was dried, Bencic held off the American, who was the last remaining past champion in the field.
Anhelina Kalinina of Ukraine topped No. 12 seed Alize Cornet of France 7-6 (5), 7-5.