Melbourne:Novak Djokovic got a closer look at how the competition stacks up at the Australian Open when he mixed it with Serena Williams and Kim Clijsters on Sunday.
Roger Federer and Lleyton Hewitt had already teamed up against Rafael Nadal and Andy Roddick to get the Haiti earthquake relief exhibition match started on Rod Laver Arena.
Djokovic was next on, the only man on court when he partnered US Open champion Clijsters in a mixed doubles match against top-ranked Williams and Australia's Samantha Stosur.
Players, organizers and pundits have spoken animatedly about the increasing competition in women's tennis with Belgians Clijsters and Justine Henin returning from retirement, and with Maria Sharapova here for the first time since her 2008 title run.
While the competition intensifies for Serena and Venus Williams and a host of Russians led by Dinara Safina and Svetlana Kuznetsova, few expect much change in the status quo on the men's side.
With 17 of the last 19 majors between them, Federer and Nadal have set up a seemingly two-man contest at the Grand Slam tournaments.
No. 3-ranked Djokovic sees it differently.
"I think it's getting very interesting, men's tennis. It's good for the sport to have a good group of the players that are able to win," he said Sunday. "I think over the years this can be one of the most exciting Grand Slams."
Djokovic had an upset semifinal win over Federer en route to the title here two years ago.
The only other player to interrupt the Federer-Nadal domination which started at the 2005 French Open was Argentina's Juan Martin del Potro, who upset Federer to win the US Open in September.
Djokovic said del Potro's win had given extra confidence to the players ranked from No. 3 down.
"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, "and it's good for us, the group of the players that is trying to catch up. We have more belief that we can win Grand Slams."
Among them, No. 4 del Potro of Argentina, No. 5 Andy Murray and No. 7 Roddick are all in action Monday, when the bottom halves of the men's and women's draws get started. The 21-year-old del Potro withdrew from an exhibition tournament at Kooyong last week with an injured wrist, but his agent said it was precautionary and he's expected to be OK at Melbourne Park.
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 schedule under way on the Melbourne's Park's main stadium Monday morning against fellow Russian Maria Kirilinko.
Clijsters, who won the US Open in September in only her third tournament back from time off to get married and have a baby, was second match on the center court against Valerie Tetreault of Canada.
Seven-time Grand Slam winner Henin makes her Grand Slam comeback against fellow Belgian Kirsten Flipkens on 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' US Open title which 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, and comes into this tournament as defending champion and holder of the season-ending championship.
The Williams sisters are on 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 which pulled a capacity crowd of 15,000 people, who all paid AU$10 to be there.
Australian Open organizers expected more than AU$200,000 ($185,000) was raised for the earthquake victims.
It was vintage "Djoker," pulling pranks and eliciting laughs in the way he did when he first emerged in 2007 as a Grand Slam contender, who just happened to do pretty good impersonations of other players.
He got a good taste of what the women players have had to handle when he was almost felled in a volley duel he lost against 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, giving his resume a serious complexion.
"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. I love playing, traveling around, competing. I just can take that 2008 and '09 as a big lesson to my life."