'I think it will be Federer, I have to give it to him.
Seven-time grand slam winner Venus Williams has a tough opener against Belinda Bencic and will face 12th seed Julia Goerges in the fourth round if the seeds hold.
New rules reverting Grand Slams to 16 seeds from the current 32 are due to come into force in 2019.
"Along the road, I had other issues".
While Nadal and six-time Australian Open champion Novak Djokovic battle to prove their fitness following the withdrawal of five-time runner-up Andy Murray, defending champion Federer is pain-free and enjoying a relaxed build-up.
"There was a doubt, especially after I pulled out of the first week of the year", he admitted.
However, he comes into the tournament short of match practice, having barely competed since an elbow injury forced his retirement at Wimbledon in July.
Elina Svitolina [9.0] is the favourite.
Organizers defended the decision to invite Sharapova to appear as the representative for the women's draw, with tournament director Craig Tiley saying the sanction was over and the 30-year-old Russian was there as a former champion. The seventh seed may have to deal with any of Fabio Fognini (25), Tomas Berdych (19) or Juan Martin del Potro (12) if he is to get to the last eight in Melbourne.
Roger Federer is fully prepared for the expectations that will accompany him at the Australian Open, as the 36-year-old prepares to defend his title. If healthy this season - a big if for Djokovic and Nadal as it begins - they still look like the stars around which others will orbit. "Luckily for me I'm here and so I'm hoping in the next four, five days everything will go well and I'll be ready for the Open".
"When you see those type of opportunities, you need to be able to seize them", he said.
Can Maria triumph in Serena's absence?
Williams remains, at 23 Grand Slam singles titles, one short of Court's record.
Nadal overcame dogged resistance from the Austrian to win 10-8 in the much-needed hitout.
Court, a Pentecostal pastor, has strong views on homosexuality. Chris Kermode, executive chairman of the men's tour, the Association of Tennis Professionals, promised a shake-up, although he accepted the players' reasons for withdrawing.
'Unfortunately I had a snowboarding accident over the Christmas break and haven't quite recovered enough to fly out to Australia this year, ' he said at the time.
Talent he has in plenty, but the volatile Australian's potential has often been betrayed by his temperament. "No, there's no chance".