Like Federer, Nadal has pared back his playing schedule to prolong his career but the strain still showed when he pulled out of the ATP Tour Finals in November with a knee problem after losing his opening match.
"I'm hoping that it can be 100 percent at the start of the tournament".
Djokovic is seeded 14th and will be coming off just a couple of exhibition matches to prepare for his first-round encounter against Donald Young.
The world No 1 came agonisingly close to winning a second title in Melbourne previous year, losing in five thrilling sets to Roger Federer in the final.
The grand slam starts on January 15. Federer went on to win Wimbledon for his 19th major and finished the year ranked No. 2 behind Nadal, who won the French and U.S. Open titles.
"It's a new situation for me".
"I feel that I had a good week and a half of practices. I feel myself more or less playing well", he added. "That was at the US Open", he said.
He will face Dominican Victor Estrella Burgos in the first round of the Australian Open at the back of injury issues.
However, 16-time Grand Slam Champion is positive ahead of the Australian Open and is rearing to go and is motivated ahead of the tournament.
Not only can he clinch a 17th Grand Slam in Melbourne, but he also has the opportunity to join Roy Emerson and Rod Laver as only the third man in the Open era to win each of the four Grand Slams twice.
"But everyone starts from zero". I still have this afternoon and tomorrow, the last practice before the competition starts for me.
Last season gave renewed hope that Dimitrov might still blossom into the Grand Slam champion he seemed set to become as an extravagantly-talented junior. He has enough confidence with me, or I have enough confidence with him, to talk about anything I have to talk.
"I think improving the grand slam performances is one thing (he needs)", he said.
"I'm happy with the way that I am working with (coaches) Carlos (Moya), with Francis (Roig) and the rest of my team".
"In terms of professional things, I spoke to him few days ago, speaking about how the life going, how the tennis going", he said of Toni. If he has something to tell me, he calls me and tells me.