Serena Williams and Maria Sharapova reached the quarterfinals at the Madrid Open on Thursday, with the two top-ranked players winning in straight sets.

Williams needed a little more than an hour to defeat Maria Kirilenko 6-3, 6-1, after Sharapova got past Sabine Lisicki of Germany 6-2, 7-5.

Top-ranked Williams dominated Kirilenko, who dropped the first set with one of several unforced errors.

The defending champion used a strong return game, working the 12th-ranked Russian back and forth on the baseline of the red clay court with her precise forehand drives.

Williams will face Anabel Medina Garrigues of Spain, who reached the quarterfinals after Yaroslava Shvedova withdrew with a right arm injury.

Sharapova used her big serve to take the first set with relative ease, but Lisicki put up stubborn resistance in the second.

Both players traded early breaks in the second set before Sharapova converted a fourth break point when Lisicki returned her well-placed slice into the net.

Sharapova didn't waste the opportunity to serve out the match, hitting an ace and forcing Lisicki into three errors in the final game to finish the match.

"She is the kind of opponent that plays extremely well against the top players," said Sharapova, who lost to Lisicki last year at Wimbledon.

Sharapova will face either Daniela Hantuchova or Kaia Kanepi next.

The Madrid Open is a key warm-up tournament for the French Open, where Sharapova will try to defend her title.

"(Last year) was an incredible memory for me and one that I will have the rest of my life," she said. "I'm still very hungry to win it. When I have that type of attitude I work harder to that goal. I find a lot of motivation at going back and trying to defend my title."

Also Thursday, Roger Federer and Rafael Nadal will play third-round matches.