Australians Samantha Stosur and Daria Gavrilova have been eliminated in the third round of the Charleston WTA event.
Stosur's serve again proved problematic and was broken in eight of her 11 service games en route to the 6-4, 7-6 (7-5) loss to Italian Sara Errani. 
The No.10 seed and 2010 Charleston champion won just 23 of 66 points on her own serve and only stayed in the second set when she broke Errani twice.
Gavrilova then went down in straight sets to American Sloane Stephens, losing 6-4, 6-3.
Venus Williams is also out after losing to Yulia Putintseva, of Kazakhstan, 7-6 (7-5), 2-6, 6-4.
Williams, seeded third and ranked 14th in the world, had a chance to gain a place in the top 10 had she won this match.
Instead, Putintseva won five of the final six games to advance.
Williams became the fifth of the top eight seeds in Charleston to lose before the quarter-finals.
Top-seeded Angelique Kerber avoided that earlier on Thursday (Friday AEST) with a 6-2, 6-3 victory over Slovakia's Kristina Kucova.
Kerber is the defending champion after winning the title in last year's Family Circle Cup.
The second-ranked German star was not at her best, but good enough to put away Kucova.
Kerber broke her opponent seven times, including the final game.