Second seed Venus Williams tumbled out of the Family Circle Cup on Thursday, succumbing 6-4, 7-6 to big-serving German Sabine Lisicki in the third round.
The American, who had to battle the previous day before beating Indian Sania Mirza in three sets, lost the match in 87 minutes after the 16th-seeded German took the tiebreak 7-5.
Williams, champion here in 2004, had never previously played Lisicki, who came from behind in both sets to seal her upset victory.
"I'll try to come back next year and win," world number five Williams told reporters. "I made some mistakes at the wrong time and she played some great shots."
In another upset on the stadium court, Hungarian left-hander Melinda Czink eliminated fourth-seeded Russian Nadia Petrova 3-6, 6-4, 7-5 in a marathon battle lasting just over two and a quarter hours.
Top-seeded Russian Elena Dementieva swept aside American Varvara Lepchenko 6-1, 6-1 and fifth-seeded Dane Caroline Wozniacki beat China's Peng Shuai, the 10th seed, 6-3, 6-4.
Sixth-seeded Frenchwoman Marion Bartoli booked her place in the last eight with a 6-4, 6-1 demolition of American Melanie Oudin while seventh-seeded Dominika Cibulkova of Slovakia recovered to beat Russian Anastasia Rodionova 6-7, 6-2, 6-3.
Elena Vesnina beat Viktoriya Kutuzova in straight sets 7-6, 7-5 while Virginie Razzano advanced when third-seeded Vera Zvonareva retired after just two games.