Rafael Nadal in particular could play himself into that role but he has not contested a match since November because of knee troubles while the fitness of six-time champion Novak Djokovic is even more uncertain after six months out with an elbow injury.

Federer, of course, knows that such transformations are eminently possible after returning from his own injury hiatus 12 months ago to win a stunning 18th grand slam title.

This time his preparation has been virtually perfect, and Federer said of his expectations: "It's totally different.

"This year I hope to win the first few rounds and get rolling hopefully, whereas last year I was just hoping to win (a match). It was more of a 'let's see what happens' kind of tournament, maybe similar to what Novak or Stan (Wawrinka) or others are going through this year.

"If you're in the draw, you give yourself a chance. That's what happened for me last year. And it ended up way better than I thought it would.

"It was the tournament of the year for me, no doubt about it. Having no expectations was so nice after all these years always having expectations, like now this year again.

"With age I feel like I play down my chances just because I don't think a 36-year-old should be a favourite of a tournament.

"I feel like maybe somebody like a Rafa, with the year that he's had, and Novak, with the six titles he's had here, even if it's unknown how he's feeling, they could very well be the favourites, too.

"It's just great to be back. I'm so, so happy the Australian Open, it's time again. I can't believe it's been a year, but it's okay. I'll make the most of it."

He may be 36 but Federer has never lost his boyish enthusiasm for tennis, which has sustained him through the different periods of his career.

This is arguably the most remarkable period of all, with the Swiss following up his Australian triumph by winning an eighth Wimbledon.

A record 20th slam title could see him return to world number one, although Nadal only needs to reach the quarter-finals to hold onto that honour.

Federer said: "I've always enjoyed it. Do I enjoy it more now? It's unfair if I say yes, because I felt like I loved the time when I was coming up and playing my heroes from TV. That was extremely cool. It's like a little boy in the candy store.

"When I was number one in the world, winning all these tournaments, that was a lot of fun, too. That was okay. Now it's different. Now I have a big family. I have a lot of friends that travel the world with me.

"It's just nice that it's never actually gone away, the fun aspect of actually enjoying the travel, coming back to Australia. It's great times in my life and in my career that we can make it all work, that I can still play tennis."

Federer will open his campaign on Tuesday against former British player Aljaz Bedene, now back representing Slovenia.