Serena, Li, Sharapova reach Madrid QFs

Madrid, Spain ( - Reigning two-time champion Serena Williams, Australian Open titlist Li Na and former No. 1 star Maria Sharapova were among Thursday's third-round winners at the $4.2 million Madrid Open, a clay court French Open tune-up.

The current 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 overcame a toe problem to come from behind and best 16th- seeded American Sloane Stephens 2-6, 6-3, 6-2 at the Magic Box.

Thursday's victory marked the 650th of Williams' brilliant career.

"She made me work for every point and it wasn't an easy win," Williams said. "She just won last week, so she is definitely not an easy player to play."

The 32-year-old Williams tallied 27 winners to Suarez Navarro's five, while converting seven break points.

Williams, who beat 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 and 2011 Madrid champ Petra Kvitova.

Meanwhile, the eighth-seeded Sharapova dismissed former U.S. Open champion and former French Open runner-up Samantha Stosur 6-4, 6-3 to setup a quarterfinal showdown with Li.

Also on Day 6, third-seeded former Wimbledon runner-up Agnieszka Radwanska rolled past Italian Roberta Vinci 6-1, 6-1; fourth-seeded Romanian Simona Halep overcame 15th-seeded Wimbledon runner-up Sabine Lisicki, of Germany, 5-7, 6-3, 6-2; the former Wimbledon champion Kvitova eased past Czech Lucie Safarova 6-4, 6-3; 11th-seeded former world No. 1 Ana Ivanovic dusted Russian Anastasia Pavlyuchenkova 6-1, 6-2; and French qualifier Caroline Garcia doused 10th-seeded former Roland Garros finalist Sara Errani, of Italy, 6-2, 4-6, 6-3.

Friday's other quarters will pit the Polish Radwanska against Garcia and Halep versus the Serbian former French Open champ Ivanovic.