'I want to thank him': Curious twist in controversial Djokovic incident

Novak Djokovic has apologised for crossing the line and touching the chair umpire during his volatile Australian Open final win on Sunday night.

Djokovic could face a $30,000 fine for twice tapping Damien Dumusois on the foot while remonstrating with the French official during his drama-charged five-set win over Dominic Thiem.

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The Serbian lost his cool when he was handed back-to-back time violations in the one game for taking too long to serve.

With the score locked at 4-4 in the second set, the second penalty came at break point and cost him a first serve, with Djokovic losing the game.

A furious Djokovic marched past the umpire's chair and tapped Dumusois's foot and sarcastically exclaimed: "You made yourself famous in this match. Great job. Especially in the second one. Great job. You made yourself famous. Well done man."

Dumusois didn't react.

But, according to the official grand slam rule book, Djokovic could find himself hit with a $US20,000 ($A30,000) fine, although penalties are discretionary.

The rules state: "Players shall not at any time physically abuse any official, opponent, spectator or other person within the precincts of the tournament site. Violation of this Section shall subject a player to a fine up to $US20,000 for each violation."

Djokovic didn't believe he'd overstepped the mark in the immediate aftermath to his victory.

"For touching his shoe? I mean, I didn't know that's completely forbidden," he said after capturing his eighth Open crown.

‘Things happen that obviously you're not proud of’

"I thought it was a nice, really friendly touch. I wasn't aggressive with him in terms of physical abuse.

"I just couldn't believe that I got the time violation. It kind of disturbed me. That's all there is to it.

"Verbally we did have some exchanges, but no insults because if I did insult him, I would get a warning.

Incredibly, the eight-time Australian Open champion then offered his thanks to chair umpire after being informed that his contact with the official could have led to an uglier outcome.

"Right now that you tell me that, I want to thank him for not giving me a warning for touching him. That's all I can say."

But in the cold light of day, the Serb conceded he wasn't happy with his conduct.

"In a professional sport, things happen that obviously you're not proud of," he said on Monday.

"Sometimes you do things that you're not happy with and you go through different emotions, you go through ups and downs.

"Of course, I'm not happy that I touched the chair umpire. And I'm sorry if I offended him or anybody else.

"But in the heat of the battle, some decisions that he makes or some decision that happens just distracts you and sets you off the balance a little bit."

Djokovic didn't believe the second violation was necessary.

"The first one, fine, no problem," he said.

"The second one, it's just not necessary under the circumstances for an experienced chair umpire.

"I thought probably he, in my opinion, could have reacted a little bit better in that situation.

"These kind of things in games switch the momentum of the match."