Former World No.1 Venus Williams lost to Yulia Putintseva of Kazakhstan 6-7 (5), 6-2, 4-6 while top-seeded and defending champion Angelique Kerber advanced to the quarter-finals with a 6-2, 6-3 victory over Slovakia's Kristina Kucova in Charleston tennis tournament.
Williams was up 2-1 in the third set of her match. But instead, the 21-year-old Putintseva won five of the final seven games to oust the 35-year-old American on Thursday, reports Xinhua news agency.
Kerber will face Irina-Camelia Begu next while Putintseva will face fifth-seeded Sara Errani, a 6-4, 7-6 (5) winner over No.10 seed Samatha Stosur. Begu topped Puerto Rico's Monica Puig 6-1, 2-6, 7-6 (4).
No.7 seed Sloane Stephens will take on 14th-seeded Daria Kasatkina of Russia. Stephens defeated 12th-seeded Daria Gavrilova of Australia 6-4, 6-3 while Kasatkina topped America's wild-card entrant Louisa Chirico 6-0, 6-4.
Russian qualifier Vesnina beat Lourdes Dominguez Lino of Spain 6-1, 6-3, setting up match-up with Germany's Laura Siegemund, who topped Mirijana Lucic-Baroni of Croatia 7-5, 6-2.
