MADRID(AP) Juan Martin del Potro of Spain advanced to the third round of the Madrid Open when Tomas Berdych was forced to retire with a leg injury on Wednesday.
The Czech player, who had won his first title of the year at the BMW Open in Munich on Sunday, retired while trailing 4-1 in the second set having lost the first set 6-2.
Seventh-seeded Victoria Azarenka eased past Peng Shuai 6-4, 6-1 at Madrid's new ``Magic Box'' tennis center. Vera Dushevina defeated Francesca Schiavone 6-3, 4-6, 6-2.
In later matches, top-seeded Rafael Nadal was to meet Jurgen Metzer, while third-seeded Novak Djokovic played Oscar Hernandez.
On the women's side, top-ranked Dinara Safina was set to play Li Na.