Milos Raonic (21), Canada, lost to Sam Querrey, United States, 6-7 (3), 7-6 (7), 7-6 (8), 6-4.

Novak Djokovic (1), Serbia, def. Radek Stepanek (28), Czech Republic, 4-6, 6-2, 6-2, 6-2.

Roger Federer (3), Switzerland, def. Julien Benneteau (29), France, 4-6, 6-7 (3), 6-2, 7-6 (6), 6-1.

Janko Tipsarevic (8), Serbia, lost to Mikhail Youzhny (26), Russia, 6-3, 6-4, 3-6, 6-3.

Nicolas Almagro (12), Spain, lost to Richard Gasquet (18), France, 6-3, 6-4, 6-4.

Juan Monaco (15), Argentina, lost to Viktor Troicki, Serbia, 7-5, 7-5, 6-3.

Fernando Verdasco (17), Spain, lost to Xavier Malisse, Belgium, 1-6, 7-6 (5), 6-1, 4-6, 6-3.

Richard Gasquet (18), France, def. Nicolas Almagro (12), Spain, 6-3, 6-4, 6-4.

Mikhail Youzhny (26), Russia, def. Janko Tipsarevic (8), Serbia, 6-3, 6-4, 3-6, 6-3.

Radek Stepanek (28), Czech Republic, lost to Novak Djokovic (1), Serbia, 4-6, 6-2, 6-2, 6-2.

Julien Benneteau (29), France, lost to Roger Federer (3), Switzerland, 4-6, 6-7 (3), 6-2, 7-6 (6), 6-1.

Florian Mayer (31), Germany, def. Jerzy Janowicz, Poland, 7-6 (5), 3-6, 3-6, 6-3, 7-5.

Anabel Medina Garrigues (26), Spain, lost to Jana Cepelova, Slovakia, 6-7 (7), 7-6 (5), 6-3.

Maria Sharapova (1), Russia, def. Hsieh Su-wei, Taiwan, 6-1, 6-4.

Agnieszka Radwanska (3), Poland, def. Heather Watson, Britain, 6-0, 6-2.

Angelique Kerber (8), Germany, def. Christina McHale (28), United States, 6-2, 6-3.

Vera Zvonareva (12), Russia, lost to Kim Clijsters, Belgium, 6-3, 4-3, retired.

Sabine Lisicki (15), Germany, def. Sloane Stephens, United States, 7-6 (5), 1-6, 6-2.

Maria Kirilenko (17), Russia, def. Sorana Cirstea, Romania, 6-3, 6-1.

Nadia Petrova (20), Russia, lost to Camila Giorgi, Italy, 6-3, 7-6 (6).

Christina McHale (28), United States, lost to Angelique Kerber (8), Germany, 6-2, 6-3.

Peng Shuai (30), China, def. Arantxa Rus, Netherlands, 6-1, 6-2.