Azarenka, one of six women who can finish atop the rankings depending on results at Melbourne Park, is coming off a win at the Sydney International last week. “Well, the score is easy. To actually play the match, it's never easy, especially for me coming here only Saturday”, she said, adding she was unsettled because she had to get to Melbourne Park so early there was nowhere open to buy her morning coffee.

“First time I actually hit on centre court was today in the morning”, she said.

The Sydney champion has gone on to reach the Australian Open final six times since 1997, winning twice. Li Na won in Sydney last year but lost the Australian Open final to Kim Clijsters two weeks later. Li, who became the first player from China to win a Grand Slam singles title with her victory at the French Open last year, advanced to the second round with a 6-3, 6-1 win over Ksenia Pervak of Kazakhstan. Clijsters was also in action later Monday.

Azarenka beat Li in the Sydney final Friday night and is starting to gain a following in Melbourne's Chinese community. “After beating Li Na, a lot of Chinese people started recognizing me”, the 22-year-old from Belarus said about her experience at a Chinese restaurant. “That's a plus.”

She'll get more local attention in coming days, with a second-round match against Australian wild-card entry Casey Dellacqua, a 6-3, 6-2 winner over Serbia's Bojana Jovanovski.

Eighth-ranked Agnieszka Radwanska can take the top ranking by winning the Australian title. She had a battle on her hands just to make the second round, fending off American Bethanie Mattek-Sands 6-7 (10), 6-4, 6-2 in a three-hour match on Show Court 2. Mattek-Sands hit a stunning 81 winners but also had 65 unforced errors.

Radwanska remained composed after trading breaks early in the third set, winning five of the last six games.

Other women advancing included No. 20 Daniela Hantuchova of Slovakia, No. 26-seeded Anabel Medina of Spain and Eleni Daniilidou of Greece beat 41-year-old Kimiko Date-Krumm of Japan 6-3, 6-2.

No. 30 Kevin Anderson of South Africa was the first man into the second round, beating Denmark's Frederik Nielsen 6-1, 6-2, 6-4, while 2009 US Open champion Juan Martin del Potro dropped the first set to France's Adrian Mannarino before advancing 2-6, 6-1, 7-5, 6-4.

Eighth-seeded Mardy Fish, the highest ranked of the U.S. men, had a 6-4, 6-4, 6-2 win over Gilles Muller to progress along with No. 7 Tomas Berdych, No. 10 Nicolas Almagro and No. 18 Feliciano Lopez.

Big-serving Croatian Ivo Karlovic ousted No. 31 Jurgen Melzer and Italy's Flavio Cipolla beat Russian veteran Nikolay Davydenko -- a former world No. 3 who has played in four major semifinals _ 6-4, 4-6, 3-6, 6-2, 6-1.

After an unusually cool buildup to the tournament, players were confronted with a strong breeze and temperatures approaching 30 degrees Celsius (86 Fahrenheit) Monday.

In later matches, Clijsters was due to play Maria Joao Koehler of Portugal and top-ranked Caroline Wozniacki, still searching for her first major title, faced Australia's Anastasia Rodionova.

Roger Federer and Rafael Nadal are on the same side of the draw for the first time since 2005.

Third-seeded Federer, a four-time Australian Open winner, was set to play on Rod Laver Arena in a Monday night match against Russian qualifier Alexander Kudryavtsev. Second-ranked Nadal had the last match on Hisense Arena -- the second show court at Melbourne Park -- against Russian Alex Kuznetsov.

Nadal criticised Federer over the weekend for letting other players 'burn themselves' by complaining about tour conditions while maintaining his good reputation by rarely making negative comments about tennis.

After telling a pre-tournament news conference Sunday he had no intention of being the frontman for the players' grievances because it has reflected badly on him in the past, Nadal was then critical of 16-time Grand Slam winner Federer in a Spanish-language interview.

Responding to the suggestion that Federer disliked players complaining openly about problems on the tour because it tarnished the image of tennis, Nadal said he took another view.