MELBOURNE, Jan 13: Roger Federer has given himself the all clear from a virus bug that had his rivals hoping for a change in the tennis order at the Australian Open starting here on Monday.

Federer is vying for his 13th Grand Slam crown, edging to within one of the record held by American Pete Sampras, but had to pull out of his customary leadup Kooyong Classic exhibition to get over his health scare.

“I'm happy with my form, to be honest. Very pleased. Physically I'm fine now, too. No more issues,” he said on Sunday. “I would consider myself a hundred percent.”

Records continue to roll off the Federer racquet and the Swiss champion is bidding to become only the third player in history and the first since 1965 to win a hat-trick of Australian Opens.

He will become just the fifth player in the long history of men's tennis to go away with four or more Australian titles and is chasing three successive Grand Slam titles for the third time.

Such is the 26-year-old's domination, that the question begs who can stop the Fed Express from claiming his ninth of the last 11 major tournaments, with world No 2 Rafael Nadal picking up the last two French Opens.

If his health is not an issue, then it will come down to who has the game over the next fortnight to stop who many regard as the greatest player of all time from adding the 2008 Australian title to his burgeoning trophy cabinet.

Federer has been unchallenged as world No 1 since February 2004 and has won three of last year's four Grand Slams for the third time in four years.

Federer plays Argentina's Diego Hartfield in his opening match on Tuesday.

Federer's main rivals appear to be the younger brigade, headed by second seed Nadal, third-ranked Serbian Novak Djokovic and British ninth seed Andy Murray.

Nadal had a setback in his Australian Open buildup when he suffered an embarrassing defeat to Russian Mikhail Youzhny 6-0, 6-1 at the Chennai Open final.

“This is first important tournament of the season. It's going to be interesting. I'm going to try my best. I think I am prepared,” Nadal said ahead of his opener against Serbia's Viktor Troicki on Monday.

“I'm not worried about Roger, he is better than the other guys at the moment. But a lot of young guys are coming from behind at the present time.”

Djokovic, refreshed after late season burn-out last year, will be looking to mount a serious challenge to Federer here after having chances against the Swiss in last year's US Open final.

“As a 20-year-old, I reached the third place of the world, but I'm really not trying to rush anywhere,” Djokovic said.

“Roger and Rafael's rivalry is the biggest in men's tennis, but I've been making a lot of good results and people have started talking about there being more about three players, not any more just two.”

Murray won the Qatar Open on his way to Australia and the 20-year-old Scot rates his chances on the new Australian Plexicushion surface.

“I feel I play better tennis in Australia than at (his favourite event) the US Open. But there are lots of guys who play well on hardcourt,” he said.

Meanwhile, the women’s top ranked player Justine Henin enters the year’s first major event high on confidence and in the form of her life but must fend off a strong field of challengers to claim her seventh Grand Slam.

Among those gunning for the Belgian is defending champion Serena Williams, looking fitter and sharper than the player who stunned the tennis world by claiming the title last year after a career-threatening injury layoff.

Russian Maria Sharapova, last year's beaten finalist, has also warned opponents write her off at their peril, while compatriot Svetlana Kuznetsova is aching to end a Grand Slam drought stretching more than three years.

Serena's sister Venus is another tour veteran considered a chance of lifting the trophy, combining the experience of a six-time Grand Slam winner with the hunger to win her maiden Australian Open title.

A number of rising stars will also be in contention, including the Serbian pair Jelena Jankovic and Ana Ivanovic, both looking to build on outstanding performances in 2007 that saw them break into the top five.

France's Amelie Mauresmo took her career to a new level when she won here in 2006 and will be hoping Melbourne Park can provide her with the inspiration to turn around last year's injury-plagued season, when her ranking slipped to 18.

But Henin, who won here in 2004 and controversially walked off centre court midway through the 2006 final against Mauresmo with a stomach complaint, remains the player to beat.

The Belgian finished 2007 with 10 titles, including the US and French Opens.

IHenin said she felt she had grown up in 2007 and felt more relaxed than at any other time in her career, ominously warning that her best tennis was yet to come.

Despite her confidence, she admitted that her nightmare 2006 final provided an extra spur to claim the Australian title this year.

“I don't have the feeling I have to prove anything to anyone,” she said.“I just have a lot of motivation because it's a tournament I like a lot and because two years ago I couldn't be at my best and I couldn't get my chances to win another Grand Slam.”

Serena Williams said she was determined to claim Henin's No 1 spot this year after shaking off a series of groin, calf and thumb problems that marred her season after her Australian Open triumph.

“I like my preparation this year,” she said.

“I don't feel any pressure at all. I feel just, you know, excited to be here. I don't feel like, 'Oh, my God, I have to win, win, win'. I just feel like I'm having so much fun every day.”

Sharapova, who fell to number five in the rankings as she struggled with injury in 2007, said her will to win meant she was always a threat at Grand Slams.

“I don't think you can ever count me out,” she said. “No matter how confident or not, no matter where my ranking is, you know, I'm one of the toughest competitors out there.

“I never leave the court without giving a hundred percent.”

—AFP