Rafael Nadal labelled Novak Djokovic's Australian Open final performance "unbelievable" and felt he lacked the match practice to compete with the Serbian.

Djokovic thrashed Nadal 6-3 6-2 6-3 in Melbourne on Sunday to win a record seventh Australian Open title and 15th major crown, moving him past Pete Sampras and into outright third on the all-time list.

Playing competitively for the first time since last year's US Open and coming off ankle surgery, Nadal was dominated on Rod Laver Arena.

Asked about Djokovic's performance, Nadal paid tribute to the 31-year-old, but said a lack of matches hurt his chances against his rival.

"He played I think fantastic. At the same time, it's true that when he's playing that way, I think I needed something else," the Spaniard told a news conference.

"I was not able to have that extra thing, being honest. It was unbelievable the way that he played, no doubt about that.

"But at the same time it's true that probably physically I was not able. I played fantastic tennis during both weeks, it's true, but probably playing that well, I didn't suffer much during both weeks.

"Five months without competing, having that big challenge in front of me, I needed something else. That something else probably, I don't have it yet. That's my feeling, to compete at this super high level.

"I think I was playing great during the both weeks in offensive positions. In defensive positions, I practiced what I practiced. I practiced well, very well I think, but because of the things that happened to me in terms of surgery, then what happened in Abu Dhabi, I was not able to work that much the defensive game. I worked a lot on the offensive game, but not that much on the defensive game.

"To play against a player like him, playing the way he played, I needed that defensive game to finally have the chance to be offensive. When he was hitting, it's true that maybe it was difficult to beat him even if I was at my 100 per cent. But probably it will be a little bit more of a fight."

Djokovic made a flying start and never looked back, Nadal committing 11 of his 28 unforced errors in the first set.

But the 17-time grand slam champion dismissed any suggestions nerves played a part early in the encounter.

"What on other days have been a serve and a ball that I can have in offensive position, today have been in defensive position. That's not nerves. That's things that happened quicker than what happened the previous days," Nadal said.

"I don't like to say he played unbelievably well because it looks like you find an excuse for yourself. The real thing is he played so well. He did a lot of things very difficult unbelievably well. He hit so long. His return was fantastic. He was super quick.

"I really believe that he was able to work very hard in the off-season on his movement. He was moving unbelievably well. I felt that good shots came back with offensive position for me, after not a bad shot from me, I have been in the defensive position."