MELBOURNE, Australia — Rafael Nadal ditched his trademark sleeveless top in favor of a more conservative T-shirt.

His bulging biceps may no longer be exposed to view, but they're certainly still driving the top-ranked player's muscular approach to the game.

The 22-year-old Spaniard bullied Christophe Rochus around Rod Laver Arena on Tuesday night with some brutal forehands and 10 aces in a 6-0, 6-2, 6-2 first-round win at the Australian Open.

He hit 47 winners in 22 games and Rochus, a Belgian who turned 30 last month, could get nowhere near most of them.

Having the last match of the opening round had its advantages for Nadal. He'd already had a chance to see how Roger Federer, defending champion Novak Djokovic and fourth-ranked Andy Murray had progressed.

He would get another look at Federer and Djokovic in the second round Wednesday. Match two in Federer's quest to tie Pete Sampras' record 14th Grand Slam title is against Russian Evgeny Korolev.

Nadal deflected a question about his intentions with such an aggressive start. He was less interested in upping the ante on his highly ranked rivals, he said, than in gauging himself after a 1½-month layoff for tendinitis in his right knee.

"I am no thinking nothing about this," he said. "I just think about try to play well myself. Roger and Novak and Murray, they are far (away) in the draw.

"I just can play with them in semifinals or finals, no? I have to think (only) about next match right now."

His next match is against 26-year-old Croatian Roko Karanusic, who was ranked 92nd and has never gone past the second round at a major.

No. 9 James Blake beat Canadian Frank Dancevic 6-4, 6-3, 7-5 in the other night match, joining fellow American men — No. 7 Andy Roddick, Mardy Fish and Amer Delic — in the second round. The other three are in action Wednesday.

The Williams sisters navigated the first step in the path to a potential semifinal showdown and, rather than do their own thing on the days between singles matches, have decided to team up in the doubles.

Serena Williams opened her campaign for a 10th major — and to continue her odd-year pattern of Australian titles that stretches back to 2003 — with a 6-3, 6-2 victory over 123rd-ranked Yuan Meng.

The temperature topped 104 degrees during the match, prompting Williams to finish points quickly, spend time in the shade and conserve fuel.

"I was able to just take my time and play a lot slower, not giving 1,000 percent," she said. "I think it was pretty important for me not to ... go crazy out there."

The temperature had dropped to 79 degrees for Venus Williams 6-3, 6-3 win over Angelique Kerber of Germany.

Olympic gold medalist Elena Dementieva beat Germany's Kristina Barrois to extend her winning streak to 11 matches. No. 13 Victoria Azarenka of Belarus and 2006 champion Amelie Mauresmo of France also made it through.

Murray needed only 12 games and 45 minutes to reach the second round, advancing when Andrei Pavel retired while trailing 6-2, 3-1 due to a back problem.

Since his career-best run to the final at the U.S. Open, he's grown in confidence and is now talking openly about "going one better."

He lost to Federer at the U.S. Open, but has beaten the Swiss star three times since then. He's also had two wins over Nadal and one over third-ranked Djokovic.

The 21-year-old Scotsman is not the only one encouraged by the run: British bookmakers are listing him as co-favorite to win the Australian Open.

Fifth-seeded Jo-Wilfried Tsonga, the Muhammad Ali lookalike who launched his run at the last Australian final with a win over Murray and beat Nadal in the semifinals, started this time with a 6-4, 6-4, 6-0 win over Juan Monaco of Argentina.

Fellow Frenchman No. 6 Gilles Simon and No. 24 Richard Gasquet also advanced.

No. 13 Fernando Gonzalez of Chile, runner-up here to Federer in 2007, ended Lleyton Hewitt's 13th Australian Open. Hewitt, the 2001 U.S. Open and 2002 Wimbledon champion, lost the 2005 final here to Marat Safin.

Nadal has never reached the Australian final, but has improved one round each time he's come back to Melbourne Park. If that trend continues, he'll be in the championship match this time.

He's never won a Grand Slam on a hard court, but won the Olympic gold medal in Beijing in August last year and had a tour-high 46-10 record on the surface.

That was better than Federer (34-10), who has won eight of his 13 majors on the hard courts in New York or Melbourne.

Rochus is touting Nadal, who beat Federer in the French Open and Wimbledon finals and usurped his No. 1 ranking last year. Rochus was playing his 31st Grand Slam tournament and couldn't remember getting so badly mauled.

He later joked that the this Grand Slam event — only his second since the 2007 French Open — would be his last.

"He was going full power on every shot, and to every corner of the court," Rochus said, still shaking his head long after the match. "He was really impressive. He was confident, he knew he had almost no chance to lose."

Nadal had no mercy, stalking the baseline with a menacing look, seemingly concentrating on each point as if it was a breakpoint chance against him. He didn't need the practice, not having to face any of those.

"You know, the sport is like this," he said. "Because if you are not playing all the time 100 percent — if I had some mistakes in some moments — he can come close back to me and anything can happen."

Nadal didn't say whether the new white, gray and blue T-shirt he wore against Rochus was an attempt for a more mature look, or that it would be a permanent fixture.

Only that it was just for a change.

"I feel good. Well, in this moment I'm going to play like this," he said. "You never know in the future."