The Serb won three of the four Grand Slam titles in 2011 and started the year by winning 41 consecutive matches, not losing until June.
Most pundits feel he will struggle to emulate those feats, but the man himself told the media ahead of the Australian Open, which starts on Monday, that "everything is possible".
The defending champion said: "Obviously 2011 was the best year of my career and it's going to be very difficult to repeat what I have done, but I've done it once, why not again?
"Why not stay positive and optimistic about the whole season?
"I feel that I'm at the peak of my career.
"I feel that physically, mentally, game-wise I'm right up there.
"I can perform equally well on any surface, as I proved in 2011. That's my focus."
Roger Federer is sure to be one of the biggest threats to Djokovic's dominance in 2012 and the Swiss, without a grand slam title since winning in Melbourne in 2010, predicts there will be plenty of other players threatening this year.
He said: "I think we have a good year in store because right behind the top four are some very good players at the moment who can really break through.
"Some of them really showed again how good they were at the World Tour Finals.
"I don't quite know what's going to happen but I feel good about my own chances. But then again, that doesn't mean much because the others are really playing well at the moment."