MELBOURNE, Jan 13, 2010 (AFP) - Defending champion Serena Williams heads into the Australian Open as firm favourite but the return of Justine Henin and Kim Clijsters adds an enticing twist to the opening Grand Slam of the season.
A dominant Williams crushed Dinara Safina in the final last year and went on to claim the Wimbledon title, improving her collection to 11 majors as she ended the season as world number one.
Opting to start her year at the Sydney International this week, the American insisted she didn't feel any extra pressure with the Belgian pair coming out of retirement.
"I don't think about it a lot. I've got a lot on my plate. Everyone assumes that I'm number one anyway," she said.
"My main goals are always to stay healthy and that's a huge goal for any athlete.
"For me, it's all about doing the best that I can. Obviously, I love playing well in all the Grand Slams and I hate to lose, regardless of where it is."
She is gunning for her fifth Australian title and is one of only three players in the field to have lifted the trophy -- Maria Sharapova and Henin are the others.
World number two Safina is back to try and avenge her humiliating defeat to Williams in less than an hour last year, but she has been hampered by a back injury.
It forced her out of tennis in October but the Russian said all is now well and she is confident of challenging for the title once again.
"I'm 100 percent. I'm ready to play," she said.
"If I play my best, let's see what can happen."
She leads a strong Russian challenge which also includes Svetlana Kuznetsova, Elena Dementieva, and Vera Zvonareva -- all top 10 players.
Also back in business after a long lay-off with a shoulder injury is Sharapova, the 2008 champion and former world number one.
She said she was feeling fit and raring to reclaim her place in the top 10.
"I keep getting stronger. I'm ready for the challenge (in Australia) -- mentally and physically," said the 22-year-old, now ranked 14.
"Obviously I stepped away because I had to," she added.
"It was frustrating -- very frustrating. And boring.... But there is no better healer than time."
Serena's sister, Venus, will also be a threat but it is the return to Melbourne of Clijsters and Henin that has whetted appetites.
Clijsters, a crowd favourite in Australia, retired in May 2007 to have a baby but made a partial comeback last year which saw her sensationally win the US Open.
This year is her first full season back on tour and few will bet against her making the second week of the tournament after beating Henin to win the Brisbane International last week.
"I think we are both capable of getting back into the top 10 and I think it won't take long for Justine to have a crack at that," she said.
Henin retired in May 2008 when world number one with seven Grand Slam titles, including the 2004 Australian Open, citing a lack of desire.
But the lure of the game has drawn her back and she looks as good as she ever.
Now 27, she injured her leg late in the Brisbane final, but said the tournament had given her a big boost ahead of the Open.
"I'm really happy, it gives me the confidence I need before the Open," she said.
Others players in contention include popular Serb Jelena Jankovic and her compatriot Ana Ivanovic, who is desperate to recover from a disappointing 2009 when she slumped to 22 in the world after a run of injuries and poor form.
