Roberta Vinci was one of the first winners of the weekend, beating Dominika Cibulkova on Saturday.
Andrea Hlavackova lost a tough first set to Maria Kirilenko, 7-5, but afterwards she would come alive.
Maria Kirilenko was coming off a career-best summer, highlighted by reaching the finals of New Haven.
But Andrea Hlavackova was too tough, winning, 57 64 64, to reach her first Grand Slam second week.
Serena Williams ran away with it from 4-all in the first set against Ekaterina Makarova, winning, 64 60.
Venus Williams was watching in the stands as Serena Williams got some revenge for a loss in Australia.
At night, Sloane Stephens was two games away from upsetting Ana Ivanovic, leading by a set and 4-3.
But Ana Ivanovic outlasted Sloane Stephens, coming back to complete a three set victory, 67(4) 64 62.
Sam Stosur became the first woman into the quarters, beating Laura Robson in a tight two-setter, 64 64.
Victoria Azarenka and later Marion Bartoli joined Sam Stosur in the quarters with victories at night.
Nadia Petrova seemed headed for a big upset on Ashe, leading Maria Sharapova 2-0 in the third set.
But Maria Sharapova kept her perfect three set record for 2012 intact, pulling it out, 61 46 64.