Venus crashes out in Madrid

The American wild card was never in the contest as Kerber raced to a 6-4 6-1 win in little more than an hour.

The seven-time grand slam champion was broken six times as she won just 57% of points on her first serve and 33% on her second.

Australia's Samantha Stosur, the US Open champion and fifth seed, finished with a flourish as she battled to a 2-6 6-4 6-0 win over Christina McHale from the United States.

Stosur struggled with her serve in the first two sets and was broken twice in each, but found her range in the decider to claim victory in just under two hours.

China's eighth seed Li Na cruised to a straightforward win with a 6-3 6-1 victory over Spanish wild card Silvia Soler-Espinosa.

Na, the French Open champion, broke five times from 10 break points as he punished her opponent's poor serving.

Czech Republic's Petra Cetkovska joined them in the third round thanks to a 6-4 7-5 success over Spanish qualifier Lourdes Dominguez Lino.

In the first round, Wimbledon champion Petra Kvitova, the third-seeded Czech, beat New Zealand's Marina Erakovic 6-2 6-3.

Serena Williams, the ninth seed, also enjoyed an easy win, seeing off Russia's Elena Vesnina 6-3 6-1.

But 15th-seeded Serbian Jelena Jankovic went out, beaten 4-6 7-6 (7/5) 6-4 by Spanish wild card Carla Suarez Navarro.

Lucie Safarova, Sara Errani, Ekaterina Makarova, Lucie Hradecka, Lucie Safarova and Andrea Hlavackova also went through to round two.

In the first round of the men's draw, 11th seed Nicolas Almagro of Spain battled back from a set down to defeat Colombia's Santiago Giraldo 6-7 (5/7) 6-3 6-3.

Serbia's Viktor Troicki was also taken to three sets as he saw off American Donald Young 6-1 4-6 6-1, while Spain's Guillermo Garcia-Lopez was a 6-4 3-6 6-4 winner over Cypriot Marcos Baghdatis.

Russia's Mikhail Youzhny had a rather smoother passage as he defeated Javier Marti of Spain 6-3 6-2.

Also through to the second round are Ryan Harrison, Daniel Gimeno-Traver, Igor Andreev and Alejandro Falla.