World number one Novak Djokovic has labelled his historic Australian Open win against close rival Rafael Nadal as the greatest moment of his career.Djokovic outlasted 10-time Grand Slam winner Nadal to clinch an epic five-setter that went five hours 53 minutes."It was the longest Grand Slam final of all time. Just hearing that fact makes me cry," said the emotional Serbian."Wimbledon is right up there because it is the tournament I always wanted to win. But this comes out on top."Defending champion Djokovic lifted the title for the third time after Sunday's 5-7 6-4 6-2 6-7 (5-7) 7-5 success against second seed Nadal.It moved the 24-year-old alongside Andre Agassi, Roger Federer and Mats Wilander as the only Open-era players to have achieved a hat-trick of successes.Djokovic said: "I am very proud to be a part of history, to be among the elite group of players who have won this trophy several times."I had lots of chances to finish the match in the fourth, but he came up with some incredible serves and incredible points."So he deserved to prolong the match in the fifth set, and then really both of us could have won the match."Even when I was 4-2 down I still pushed myself up to the limit."I'm sure any other tennis player would say the same. We live for these matches."We're trying to dedicate all our life to this sport, to come to the situation where we play a six-hour match for a Grand Slam title."Djokovic reached the Melbourne final after overcoming breathing and injury problems in his quarter-final victory over David Ferrer.He also appeared to struggle physically during his semi-final defeat of Britain's Andy Murray, in a match which lasted four hours 50 minutes.But he managed to outlast Nadal in an exhausting encounter before falling to the floor in celebration following his winning point."I overcame everything," said the Serb. "That's the most important thing for me. And to be able to mentally hang in there."It was obvious on the court for everybody who has watched the match that both of us, physically, took the last drop of energy that we had from our bodies."It was just the matter of maybe luck in some moments and a matter of wanting this more than maybe other players in the certain point. It's just an incredible effort."Nadal, aiming for his second Australian Open title after beating Roger Federer in the 2009 final, said the epic encounter was one of the toughest matches of his career."We played a nice tennis match, it was a very good show and I enjoyed being a part of it," said the Spaniard."I wanted to win but I am happy with how I did."When asked if he would watch a re-run of the match, Nadal joked: "No, it's too long. Just the highlights."