Roger Federer, Amelie Mauresmo, Maria Sharapova, Marat Safin and Andre Agassi advanced to the fourth round of the Australian Open in Melbourne on Friday.

Top seed Roger Federer marched into the next round after his opponent Jarkko Nieminen retired with an abdominal injury at a time when Federer was leading 6-3, 5-2.

Women's second seed Mauresmo beat 17-year-old Ana Ivanovic from Serbia and Montenegro 6-2, 7-5. In the first set, Mauresmo had a perfect score of points won at the net -- 100 perent.

Although the percentage dipped only a little to 92 percent in the second set, she faced unexpected stronger resistance from her opponent before managing a final win.

Safin, former US Open championship and dual finalist at Melbourne Park, overcame a second set loss and defeated Croat Mario Ancic 6-4, 3-6, 6-3, 6-4 win.

Agassi defeated American rival Taylor Dent in straight sets in their third round clash 7-5, 7-6, 6-1 in 112 minutes.

Fourth seed Sharapova, the Wimbledon champion, cast aside Li Na of China 6-0, 6-2, advancing into the top 16.

The 17-year-old Russia will play 15th seed Silvia Farina Elia of Italy in the next round.

Seventh seed Serena Williams demolished Indian teenager Sania Mirza 6-1, 6-4.

After winning the first set easily, Williams faced strong resistance from Mirza who overcame her nerves and did her best fighting back.

Fifth seed Russian Svetlana Kuznetsova beat Argentinian Mariana Diaz-Oliva 6-3, 7-6.

But French Open champion Gaston Gaudio, 10th seed at Australian Open, was outclassed by Slovakian Dominik Hrbaty 7-6, 6-7, 6-7, 6-1, 6-3.

However, the loss equalled Gaudio's best performance at the Australian Open, a third round appearance in 2003.