Andy Murray (4), Britain, def. Marcos Baghdatis, Cyprus, 7-5, 3-6, 7-5, 6-1.

Jo-Wilfried Tsonga (5), France, def. Lukas Lacko, Slovakia, 6-4, 6-3, 6-3.

David Ferrer (7), Spain, def. Andy Roddick (30), United States, 2-6, 7-6 (8), 6-4, 6-3.

Juan Martin del Potro (9), Argentina, def. Kei Nishikori (19), Japan, 6-3, 7-6 (3), 6-1.

Mardy Fish (10), United States, def. David Goffin, Belgium, 6-3, 7-6 (6), 7-6 (6).

Marin Cilic (16), Croatia, def. Sam Querrey, United States, 7-6 (6), 6-4, 6-7 (2), 6-7 (3), 17-15.

Kei Nishikori (19), Japan, lost to Juan Martin del Potro (9), Argentina, 6-3, 7-6 (3), 6-1.

Philipp Kohlschreiber (27), Germany, def. Lukas Rosol, Czech Republic, 6-2, 6-3, 7-6 (6).

Andy Roddick (30), United States, lost to David Ferrer (7), Spain, 2-6, 7-6 (8), 6-4, 6-3.

Victoria Azarenka (2), Belarus, def. Jana Cepelova, Slovakia, 6-3, 6-3.

Petra Kvitova (4), Czech Republic, def. Varvara Lepchenko, United States, 6-1, 6-0.

Serena Williams (6), United States, def. Zheng Jie (25), China, 6-7 (5), 6-2, 9-7.

Sara Errani (10), Italy, lost to Yaroslava Shvedova, Kazakhstan, 6-0, 6-4.

Ana Ivanovic (14), Serbia, def. Julia Goerges (22), Germany, 3-6, 6-3, 6-4.

Roberta Vinci (21), Italy, def. Mirjana Lucic, Croatia, 7-6 (4), 7-6 (3).

Julia Goerges (22), Germany, lost to Ana Ivanovic (14), Serbia, 3-6, 6-3, 6-4.

Francesca Schiavone (24), Italy, def. Klara Zakopalova, Czech Republic, 6-0, 6-4.

Zheng Jie (25), China, lost to Serena Williams (6), United States, 6-7 (5), 6-2, 9-7.