Sara Errani of Italy was the lone seeded player in action Saturday to start the Madrid Open and the 2012 French Open runner-up had an easy win against Poland's Urszula Radwanska.
The seventh-seeded Errani was coming off a surprising loss in her Stuttgart opener two weeks ago, but cruised to a 6-3, 6-1 win Saturday. She's already had a strong 2013 campaign, winning the Acapulco title in March with runner-up finishes at the Paris Indoors and Dubai in February.
Other winners Saturday on the clay courts of the Magic Box included Slovakia's Daniela Hantuchova, Belgium's Kirsten Flipkens, Frenchwoman Alize Cornet and Germans Sabine Lisicki and Julia Goerges.
Hantuchova knocked off American Sloane Stephens, 6-3, 7-5, while Flipkens dominated Germany's Mona Barthel, 6-4, 6-1, and Cornet outlasted Dutchwoman Kiki Bertens, 7-5, 7-6 (10-8). Lisicki breezed past Sweden's Sofia Arvidsson, 6-3, 6-1, and Goerges toppled Serbia's Bojana Jovanovski, 6-4, 6-1.
Also, Britain's Laura Robson rallied for a 6-7 (4-7), 6-2, 6-2 triumph over Slovakia's Magdalena Rybarikova. Spain's Lourdes Dominguez Lino defeated Romania's Simona Halep, 6-2, 4-6, 6-4.
Serena Williams doused reigning two-time runner-up Victoria Azarenka in last year's Madrid finale and is this year's top seed. Williams will play qualifier Yulia Putintseva of Kazakhstan on Sunday.
Fourth-seeded Agnieszka Radwanska is also slated for action Sunday against Bulgaria's Tsvetana Pironkova, while fifth-seeded Li Na is set to take on Austria's Tamira Paszek.