Serena, Li reach Madrid quarters

Madrid, Spain ( - Reigning two-time champion Serena Williams and Australian Open titlist Li Na were among Thursday's third-round winners at the $4.2 million Madrid Open, a clay court French Open tune-up.

The world No. 1 superstar Williams cooled off last week's Portugal Open champion and 14th seed Carla Suarez Navarro, of Spain, 6-2, 6-3, while the second-ranked Li came from behind to best 16th-seeded American Sloane Stephens 2-6, 6-3, 6-2 at the Magic Box.

Williams, who beat former No. 1 star Maria Sharapova in last year's Madrid and French Open finals, has now won her last 15 matches in Madrid. Her quarterfinal opponent on Friday will be fifth-seeded Czech slugger Petra Kvitova.

Also on Day 6, third-seeded former Wimbledon runner-up Agnieszka Radwanska rolled past Italian Roberta Vinci 6-1, 6-1 and the former Wimbledon champion Kvitova eased past Czech Lucie Safarova 6-4, 6-3.