Sharapova, Serena reach Madrid Open quarters

Second seed and former world No. 1 Maria Sharapova enjoyed a walkover into the quarterfinals, while a battle of former top-ranked stars saw Serena Williams oust Caroline Wozniacki at the $5.190 million Madrid Open, a French Open tuneup being staged on an unusual blue clay surface.

Sharapova and Williams will meet in a marquee quarter here on Friday.

The ninth-seeded Williams started off slow before charging back to best a sixth-seeded Wozniacki, 1-6, 6-3, 6-2, at The Magic Box. Wozniacki was the Madrid runner-up three years ago.

After playing poorly in the opening set, Williams broke Wozniacki at love in the fifth game of the second and fired a forehand return winner for another break that put her up 4-3. The American great would cruise from there.

Williams is now a perfect 10-0 on clay this season.

The 30-year-old Williams improved to 4-1 lifetime against Wozniacki, who beat the powerful American in a quarterfinal in Miami earlier this year.

Sharapova was scheduled to meet Lucie Safarova in the third round on Thursday, but the Czech pulled out of their bout due to an illness.

The Russian star will face Williams for a 10th time on Friday, with the 13- time major champion Williams holding a commanding 7-2 lead in their all- time series. The American has won their last six matchups and Sharapova hasn't prevailed against Williams since a final at the 2004 WTA Championships. A then-teenaged Sharapova also shocked Williams in the '04 Wimbledon finale.

Sharapova was a clay-court titlist in Stuttgart two weeks ago, beating current world No. 1 Victoria Azarenka in the final.

Meanwhile, fourth-seeded world No. 3 Pole Agnieszka Radwanska doused Italian Roberta Vinci 7-6 (7-1), 6-4 and Czech qualifier Lucie Hradecka handled Russian Ekaterina Makarova 6-2, 7-6 (7-5). Hradecka stunned defending Madrid and Wimbledon champion and fellow Czech Petra Kvitova here on Wednesday.

Radwanska's quarterfinal opponent will be upstart American qualifier Varvara Lepchenko, who surprised quality Spanish clay-courter Anabel Medina Garrigues, 6-1, 6-7 (3-7), 6-3.

The aforementioned Azarenka, who lost to Kvitova in last year's Madrid final, will be meet eighth-seeded Chinese Li Na on Friday. The hard-hitting Li is the reigning French Open champ.

The Australian Open titlist Azarenka is a stellar 32-2 this year.

Also on Friday, fifth-seeded U.S. Open champ Sam Stosur will encounter the upstart Hradecka.

This year's Madrid Open winner will earn $830,500.