Roger Federer banished any fears about his fitness with a dazzling 6-0 6-3 6-0 win over Diego Hartfield to begin the defence of his Australian Open title.
The world number one came into tournament without any match practice after suffering a stomach virus.
But he was in devastating form in a 74-minute win, saying later: "I feel good and happy to be back playing.
"I was never in doubt of not playing here. I'm past being sick. I'm looking forward to a healthy two weeks."
Third seed Novak Djokovic of Serbia and home hope Lleyton Hewitt, seeded 19, also recorded straight-sets wins.
Djokovic beat Benjamin Becker, while Hewitt matched Federer's scoreline as he thrashed Belgium's Steve Darcis.
Djokovic showed why he is seen as a realistic challenger to Federer, who he is scheduled to meet in the semi-finals.
The 20-year-old's solid serve was matched by a ferocious return on either side and his mobility around the court was too much for his big-serving German opponent.
The German did dig in as the match progressed and made Djokovic sweat slightly in the third set before the Serb completed his victory in a tie-break.
"I started really well because I was really nervous before the match," Djokovic said after the 6-0 6-2 7-6 (7-5) victory.
"He is a good player but I was really focused at the start.
"I lost my momentum a little bit but he played well in the third set so it was good to win the first match in straight sets.
"People expect me to go far because of my results in hardcourts in 2007 but I am trying not to think about that too much, just to focus on my game - it's all about how you deal with the pressure."
Hewitt said his 77-minute demolition of Darcis had been one of his most encouraging starts to a Grand Slam in recent years.
Police had to use pepper spray in the Gonzalez-Economidis match
"It's up there definitely, I didn't do too much wrong today," said the 19th seed.
"In the end I felt I could do pretty much what I wanted to out there and play on my terms, which is good."
Hewitt next faces Uzbekistan wildcard Dennis Istomin where victory will set up a third-round meeting with 2006 finalist Marcos Baghdatis or former champion Marat Safin.
Baghdatis, the 2006 finalist, beat Thomas Johansson 7-6 6-2 3-6 6-3 to set up a mouthwatering clash with 2005 winner Safin.
Safin swept past Latvia's Ernests Gulbis 6-0 6-4 7-6.
Fernando Gonzalez, the 2007 runner-up, beat Greek qualifier Konstantinos Economidis, also in straight sets.
That match was marred by some unruly behaviour from a contingent of fans. Play was interrupted for five minutes while police restrained three people with pepper spray.
Tenth seed David Nalbandian shook off his back problems to thump Australia's Robert Smeets 6-1 6-1 7-6 (7-3) and fifth seed David Ferrer was another comfortable winner, beating France's Edouard Roger-Vasselin 6-2 6-2 6-1.
But Croatia's Ivan Ljubicic was a high-profile casualty on day two, the 17th seed tumbling out at the hands of Holland's Robin Haase, who triumphed 6-7 (2-7) 6-3 6-0 7-6 (7-1).
Most seeds in the men's draw enjoyed a smooth passage into round two on Tuesday, but Radek Stepanek was not among them.
The Czech, seeded 30th, won the first two sets easily against Vince Spadea, but the American won a close third set to stay alive and the momentum soon shifted.