AMELIA ISLAND, Fla. — Maria Sharapova got the clay-court test she was looking for, but she almost got more than she bargained for.

Sharapova outlasted clay-court veteran Anabel Medina Garrigues in three sets over 3 1/2 hours at the Bausch & Lomb Championships today.

The top seed rallied from 3-0 down in the third set and survived 7-6 (3), 5-7, 7-6 (1) to move into the quarterfinals.

"There were a lot of ups and downs in the match," said Sharapova, who is making her clay season debut at Amelia Island Plantation for the first time. "I think I should have won the match in two sets, to be honest. But I stopped hitting the ball, and I kind of let her back in the match."

Three-time Bausch & Lomb champion Lindsay Davenport beat Karolina Sprem 6-4, 3-6, 6-4 in the first night match.

Medina Garrigues controlled the momentum early in the third before Sharapova began the first of two bursts to escape.

Down 3-0, Sharapova won the next five games and saved several of her opponents' game points in the process to breathe easy at 5-3.

"It's the game of tennis, it can change really fast," Sharapova said.

It changed again as Sharapova, seemingly in control, served for the match at 5-4. Medina Garrigues won the first two points and converted her sixth break of serve to even it at 5-all.

But the tiebreak went Sharapova's way from the get-go.

The Russian won the first three and the last four points as Medina Garrigues wilted under the setting Florida sun.

This type of win a marathon with long baseline rallies against a strong clay player was just what Sharapova needed in order to prepare for the French Open.

"I still feel like I can improve," Sharapova said. "Hopefully all these matches that I play here, as many as I can, will help me toward this year's French or future clay-court matches." Sharapova entered as the tournament's top seed, ranked No. 5 in the world with a 2008 record of 19-1.

Medina Garrigues came in ranked No. 29 with no quarterfinal appearances since September but with a staunch clay reputation.

They may as well have been equals Thursday.

"This is her specialty, this is where she does best," Sharapova said. "She grew up on this stuff, and she's very familiar with it."

Amelie Mauresmo had to work hard to earn her 500th career win in the third round.

Mauresmo, the 2001 Bausch & Lomb winner, came back to beat seventh-seeded Agnieszka Radwanska 3-6, 7-5, 7-6 (6) in a match that took more than 2› hours.

Against Radwanska, Mauresmo was up 5-2 in the third before dropping two match points and then three straight games to force a tiebreaker.

"Even though I had some opportunities to finish it off before the third-set tiebreak, I couldn't make it," Mauresmo said. "I was glad that I was coming in and trying to go for it in that tiebreak. That's what made the difference, I thought, in the end."

She engineered a mini-comeback from 5-3 down in the tiebreak and closed it out with a crosscourt backhand winner that clipped the line.

"I tried to really come in and be aggressive and not let her dictate the game in the key moments, which I probably should have done a bit earlier in the match," Mauresmo said. "I finished with a positive note, so I'm glad."

Mauresmo now has won three matches in a row for the first time since Wimbledon last year.

The former world No. 1 endured a pair of two-month layoffs in 2007 with an emergency appendectomy and an adductor strain. She has struggled since and fallen to No. 24 in the rankings.

Two fellow Frenchwomen will join the 11th-seeded Mauresmo in the quarterfinals.

No. 13 Virginie Razzano defeated Olga Govortsova 6-2, 6-4, and unseeded Alize Cornet continued her run with a 6-1, 7-5 victory over Elena Vesnina.

No. 8 Agnes Szavay topped No. 12 Katarina Srebotnik 3-6, 6-2, 6-3 to secure her quarterfinal berth.