No. 2-seeded Victoria Azarenka defeated Romina Oprandi 6-2, 6-0.
British hopeful Andy Murray faced only one break point and beat big-serving Ivo Karlovic 7-5, 6-7 (5), 6-2, 7-6 (4). Kei Nishikori became the first Japanese man in 17 years to reach the third round at Wimbledon by beating Florent Serra 6-3, 7-5, 6-2.
Sara Errani committed only five unforced errors and beat Anne Keothavong of Britain 6-1, 6-1. The 25-year-old Errani, an Italian who has blossomed in Grand Slam competition this year, matched her best Wimbledon showing by advancing to the third round.
She was the French Open runner-up this month to Sharapova, and she's 12-2 in major tournaments in 2012. She began this year with a career record of 15-17 at majors.
Playing the day's first match on Court 2, the 10th-seeded Errani erased all three break points she faced and won in 61 minutes. That was a grueling effort compared with Wednesday, when she played only one point to complete a victory suspended overnight because of rain.
No. 7 David Ferrer defeated Kenny de Schepper 7-6 (1), 6-2, 6-4 and will next play Roddick. No. 13 Gilles Simon, who stirred debate this week when he said men should be paid more than women at tennis tournaments, lost to Xavier Malisse 6-4, 6-4, 7-6 (5).
Kerber beat Ekaterina Makarova 7-5, 6-3.
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