MELBOURNE, Jan. 22 (UPI) --
Andy Roddick and Lleyton Hewitt, the second and third seeds, advanced to the round of 16 Saturday in the Australian Open.
Top-seeded Lindsay Davenport was among the winners on the women's side.
Roddick won a 6-2, 6-2, 7-5 decision over Jurgen Melzer of Austria. The American fired 22 aces in the match. He next takes on German Philipp Kohlschreiber.
Hewitt, of Australia, scored a 6-2, 4-6, 6-1, 6-4 win over Juan Ignacio Chela of Argentina and will play Spain's Rafael Nadal in the next round.
Other men winning included Argentine seeds Guillermo Coria, David Nalbandian and Guillermo Canas and Russian Nickolay Davydenko, who ousted No. 7 seed Tim Henman of Britain.
Davenport, seeking her fourth Grand Slam title and second at the Australian Open, beat 15-year-old Czech Nicole Vaidisova 6-2, 6-4 and next plays Karolina Sprem of Croatia.
Russians Anastasia Myskina and Elena Dementieva, Venus Williams of the United States, Alice Molik of Australia, Nathalie Dechy of France and Patty Schnyder of Switzerland were other winners.