Melbourne, Australia ? Defending champion Amelie Mauresmo tumbled out of the Australian Open today, falling, 6-4, 6-3, to unseeded Lucie Safarova.

Safarova, the 19-year-old Czech player who had won only one match in six previous Grand Slam tournaments, faced just two break points in the fourth-round match and continually forced the French player into problems on her own serve.

“It’s amazing. I still can’t believe it,” said Safarova, ranked 70th. “I’m so happy. It’s incredible.”

Third-seeded Svetlana Kuznetsova, the 2004 U.S. Open champion, followed Mauresmo out, losing, 6-4, 6-2, to Shahar Peer.

Unseeded American Mardy Fish was the first men’s player to reach the quarterfinals, beating No. 16 David Ferrer, 6-1, 7-6 (4), 2-6, 7-5 .

He will play No. 6 Andy Roddick or No. 9 Mario Ancic in the next round.

The Mauresmo-Safarova match was played in mostly sunny conditions with the roof open at Rod Laver Arena. It was Safarova’s first time on center court in Australia and her first match against the second-seeded Mauresmo.

“I came out this morning and said, ‘Wow this is a big court.’ But I felt really comfortable here,” Safarova said.

She thanked her coach and later, her boyfriend – 13th-seeded Tomas Berdych, who beat Dmitry Tursunov, 6-2, 6-1, 6-1, in a rain-delayed third-round match.

Mauresmo had her Grand Slam breakthrough last year in Melbourne, winning her first major title seven years after reaching her first final, also in the Australian Open.

In third-round matches delayed until today by heavy rain, China’s Li Na upset No. 9 Dinara Safina, 6-2, 6-2; 12th-seeded Anna Chakvetadze beat Jelena Kostanic Tosic, 6-4, 6-4;and No. 15 Daniela Hantuchova edged Ashley Harkleroad, 6-7 (6), 7-5, 6-3. On the men’s side, No. 12 Tommy Haas beat fellow German Florian Mayer, 7-6 (3), 6-3, 6-3.