Venus Williams survived a second-set scare to edge past Sania Mirza in the Family Circle Cup in Charleston on Wednesday.

Second seed Williams breezed through the opening set but could covert only one of 11 break points as her unseeded Indian opponent rallied to take the match to a third.

The American swiftly found her feet again though, eventually winning 6-1 3-6 6-2 in a little under two and a half hours in the second round.

Fifth seed Caroline Wozniacki suffered no such alarms as she dispatched Alla Kudryavtseva 6-3 6-3, while Shuai Peng, seeded 10, needed three sets to get past Akgul Amanmuradova.

Four seeds fell, including Aleksandra Wozniak, seeded eight, who fell apart in the second set to lose 7-5 6-0 to Melanie Oudin, and ninth seed Patty Schnyder, who battled for two hours 20 minutes before crashing 6-2 6-7 (5/7) 7-5 to Elena Vesnina.

Eleventh and 12th seeds Alona Bondarenko and Bethanie Mattek-Sands fell in straight sets Viktoria Kutuzova and Anastasia Rodionova respectively.

There were also wins for Virginie Razzano, Sabine Lisicki, Varvara Lepchenko and Melinda Czink.