MELBOURNE, Australia — Novak Djokovic wonders if the old order is about to be shaken.

Yes, Roger Federer and Rafael Nadal seem to have a monopoly on Grand Slam tournaments, having won 17 of the last 19 majors between them. But with the Australian Open ready to go, Djokovic suspects change at the top may be coming.

"I think it's getting very interesting, men's tennis," he said. "It's good for the sport to have a good group of the players that are able to win. I think over the years this can be one of the most exciting Grand Slams."

Djokovic upset Federer in the Australian Open semifinals two years ago en route to the title.

The only other player to interrupt the Federer-Nadal domination, which started at the 2005 French Open, was Argentina's Juan Martin del Potro. He beat Federer to win the U.S. Open in September.

Djokovic, ranked No. 3, said del Potro's win had given players a confidence boost.

"Of course it does," he said. "The last five, six years the dominance was obvious from Federer, Nadal. They've been winning all the Grand Slams they've played. But now in last two years or so the things are changing a little bit. ... You have del Potro, Murray, Roddick, Davydenko. They're all in great shape, great form."

Djokovic said it was good for tennis.

"It's good for us, the group of the players that is trying to catch up," he said. "We have more belief that we can win Grand Slams."

No. 4 del Potro, No. 5 Andy Murray and No. 7 Roddick all play Monday, when the bottom halves of the men's and women's draws get started. Del Potro withdrew from an exhibition tournament at Kooyong last week because of an injured wrist, but his agent said he's expected to be fine for the Australian Open.

Roddick warmed up with a title run at the recent Brisbane International.

Nadal, who beat Federer in five sets in the final last year to win his first major on hardcourts, will start the night session on Rod Laver Arena against Australian Peter Luczak.

Maria Sharapova will get the schedule under way at Melbourne's Park's main stadium Monday against fellow Russian Maria Kirilinko.

Kim Clijsters was the second match on center court, facing Valerie Tetreault of Canada. Clijsters won the U.S. Open in September in only her third tournament back from time off after getting married and having a baby.

Justine Henin, a seven-time major winner, makes her Grand Slam comeback against fellow Belgian Kirsten Flipkens at Hisense Arena, the other main show court.

Henin lost to Clijsters at the Brisbane International on Jan. 9, her first tournament since she quit while holding the No. 1 ranking in May 2008. It was Clijsters' U.S. Open title that inspired the 27-year-old Henin to come back.

Serena Williams has won three of the seven majors since Henin last played the Australian Open. She enters this tournament as defending champion and winner of the season-ending championship.

She and sister Venus are in the top half of the draw and won't play their first-round matches until Tuesday.

Federer and Djokovic also get the day off Monday, which helped them stay loose for the "Hit for Haiti" fundraiser on Sunday that drew a capacity crowd of 15,000. Australian Open organizers expected more than $185,00 was raised for the earthquake victims.

Djokovic was at his vintage best, pulling pranks and eliciting laughs as he did when he first emerged in 2007 as a Grand Slam contender.

He got a good taste of what the women have had to handle when he was almost felled in a volley duel he lost against Serena Williams.

It was probably a refreshing break for Djokovic, who has had mixed receptions from crowds since he broke into the Grand Slam winners club.

"Winning a Grand Slam opened a lot of doors for me, gave me a lot of opportunities, of course, a lot of self-confidence," he said. "But, on the other hand, it took a lot of responsibility, pressure and expectations. It was all new for me. I've been through ups and downs mentally and experienced some things that I never did before.

"Right now ... I love what I'm doing," he added. "I love playing, traveling around, competing. I just can take that 2008 and '09 as a big lesson to my life."