The top-seeded Australian reeled off 18 of the final 21 games to post a 6-3, 6-2, 6-0 over unseeded Radek Stepanek of the Czech Republic and advanced to the round of 16 for the seventh time in his last eight Grand Slam events.
A year ago, the third-seeded Safin advanced to the Australian Open final. But this year, the Russian star had to abandon his title quest in the third round due to a wrist injury.
A wrist injury also ended another seed's Australian Open. No. 10 David Nalbandian owned a 4-6, 6-2, 6-0, 3-0 advantage over No. 20 Xavier Malisse of Belgium in a rematch of their Wimbledon semifinal clash in July, but Malisse was forced to retire from the match.
In women's third round action, top seed Serena Williams of the United States dropped just four points on her serve en route to a 6-1, 6-1 rout of No. 26 Tamarine Tanasugarn of Thailand, and No. 4 Kim Clijsters of Belgium overwhelmed unseeded Tatiana Poutchek of Belarus, 6-2, 6-1.
The world No. 1, Hewitt seems to have found his form, dropping just seven games in his last two contests. The Adelaide native also has matched his best-ever result at his home major with the win over Stepanek, having reached the round of 16 in 2000.
The youngest qualifier in tournament history in 1997 at the age of 15 years, 11 months, Hewitt is looking to cap his seventh straight Australian Open appearance by becoming the first home player since Mark Edmondson in 1976 to capture the title.
Hewitt will meet Morocco's Younes El Aynaoui, the 18th seed who outdueled Spain's Feliciano Lopez, 5-7, 6-2, 7-6 (7-3), 7-6 (10-8).
No. 31 Rainer Schuettler of Germany got a berth in the fourth round via walkover after Safin's withdrawal.
Safin was the top seed last week at Sydney, where he was forced to withdraw due to tendinitis in his right rotator cuff. The 2000 U.S. Open champion may be sidelined when defending Davis Cup champion Russia visits the Czech Republic in the opening round of this year's event Feb. 7-9.
Nalbandian, the runner-up to Hewitt at the All England Club, advanced to the final 16 here for the first time. At Wimbledon last summer, Malisse rallied from two sets down against Nalbandian before falling in the fifth. But on Saturday, Malisse was physically unable to repeat the comeback.
Showing his versatility, the 21-year-old Nalbandian captured the Estoril claycourt and Basel Indoor titles in 2002 as he rose 35 places in the ATP rankings to finish the year at No. 12.
Williams continued her attempt at becoming the first woman to win four consecutive Grand Slam events since Steffi Graf in 1993-94. The 21-year-old meets No. 18 Eleni Daniilidou in the fourth round. The Greek outdueled No. 16 Nathalie Dechy of France, 6-4, 6-3.
Williams' only loss in her last four majors was a setback to older sister Venus in the final of the 2001 U.S. Open. After missing last year's Australian Open with a right ankle injury, she avenged the defeat by beating her sibling in the finals ofthe French Open, Wimbledon and U.S. Open.
Clijsters continued her red-hot form in 2003. She has dropped just six games en route to the round of 16. Clijsters crushed Petra Mandula of Hungary on Thursday, 6-0, 6-0, dropping just 17 points in the 33-minute romp.
In the fourth round, the 19-year-old Belgian will face No. 19 Amanda Coetzer of South Africa, who cruised to a 6-0, 6-2 win over No. 14 Anna Pistolesi of Israel.
Clijsters captured her 11th career title last week in Sydney and has won 22 of 23 WTA Tour matches since a semifinal loss to Anastasia Myskina in September at Leipzig. Since that defeat, she has won four titles, including the season-ending championship at Los Angeles over Serena Williams.
In the men's draw, Nalbandian's next opponent is Switzerland's Roger Federer. The sixth seed converted 5-of-10 break-point chances and rolled to a 6-3, 6-4, 6-2 victory over Swedish qualifier Andreas Vinciguerra.
Russia's Mikhail Youzhny, the 25th seed, recorded a 6-1, 3-6, 6-3, 6-2 upset of Czech Jiri Novak, the seventh seed who was asemifinalist here last year. Youzhny dropped both of his meetings with Novak in 2002.
In other men's action, No. 9 Andy Roddick of the United States coasted to a 6-2, 6-3, 6-2 win over Fernando Vicente of Spain. Roddick will take on Youzhny in the round of 16.
Roddick's Davis Cup teammate, No. 23 James Blake also dealt with his unseeded Spanish opponent, posting a 6-3, 4-6, 6-2, 6-2 win over Alberto Martin. Blake will meet Schuettler in the fourth round.
In the women's draw, No. 8 Anastasia Myskina of Russia held off No. 28 Clarisa Fernandez of Argentina, 6-3, 3-6, 6-3, and next faces No. 10 Chanda Rubin of the United States, who recorded 29 winners in her 6-3, 6-2 win over qualifier Barbara Schwartz of Austria.
Bovina needed over 2 1/2 hours to edge No. 11 Magdalena Maleeva of Bulgaria, 7-5, 4-6, 7-5. Shaughnessy had a much easier time against qualifier Klara Koukalova of the Czech Republic, 6-1, 6-3.