Jarmila Gajdosova and Bethanie Mattek-Sands came from a set down to win their first doubles match.
Serena Williams did not allow Barbora Zahlavova Strycova a single winner in their first set Thursday.
Things would get closer in the second set, but Serena Williams ended up advancing with a 60 64 win.
Ana Ivanovic had few problems against former Top 30 player Michaella Krajicek, prevailing, 62 63.
Maria Sharapova met Jamie Hampton at the net after losing just one game to the American qualifier.
Maria Sharapova has now lost just two games in reaching the third round. She is the No.4 seed.
Zheng Jie extended her winning streak to seven matches with a 64 62 upset of No.23 seed Roberta Vinci.
Three-time Australian Open champion Martina Hingis made some appearances and met fans on Thursday.
Vania King had a tough time in the first set but ended up beating Anastasia Pavlyuchenkova, 57 63 64.
Sabine Lisicki was down and out in the first round but cruised through her second round in two sets.
Dominika Cibulkova served for the match at 7-6 but ended up falling to Greta Arn in a heartbreaker.
Marion Bartoli was rock solid against Jelena Dokic with an even differential of 15 winners, 15 errors.
Jelena Dokic searched for answers as she couldn't get her game on target, 17 winners to 28 errors.
Marion Bartoli only served two aces but one came at a very critical time - on match point at 63 52.
Svetlana Kuznetsova was the last winner of the day, edging young American Sloane Stephens, 76(6) 75.