Maria Sharapova was one of the first into the second week, beating junior rival Hsieh Su-Wei, 61 64.
Angelique Kerber defeated Christina McHale, 62 63, for her WTA-leading 43rd match win of the year.
Agnieszka Radwanska won the first nine games of her match against Heather Watson, taking it, 60 62.
Kim Clijsters met Vera Zvonareva at the net after Zvonareva had to retire from the match with illness.
Tamarine Tanasugarn, a former quarterfinalist in singles, served it up during her doubles match.
Alicja Rosolska and Klaudia Jans-Ignacik lost to Marina Erakovic and Tamarine Tanasugarn, 76(4) 63.
Arantxa Rus pressed hard but couldn't follow up her win over Samantha Stosur, falling to Peng Shuai.
Peng Shuai's ranking had doubled since the start of the year, No.17 to No.34, but she is coming alive.
Maria Kirilenko, the No.17 seed this fortnight, breezed against Sorana Cirstea in straight sets.
Maria Kirilenko completed her collection of Grand Slam second weeks, having done it at the other three.
Italian qualifier Camila Giorgi edged Nadia Petrova to reach her very first Grand Slam second week.
Slovakian qualifier Jana Cepelova rallied from a set and 5-2 down to beat Anabel Medina Garrigues.