'Cannot believe it': Novak Djokovic facing fine over ugly act in Australian Open final

Novak Djokovic doesn't believe he crossed the line after touching the chair umpire during a volatile Australian Open final on Sunday night.

Djokovic is facing the prospect of a hefty 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".

Novak Djokovic patted the foot of the umpire in the Australian Open final. (Photo by DAVID GRAY/AFP via Getty Images)

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."

A number of high-profile tennis figures couldn’t believe what they were seeing.

Former Aussie player Rennae Stubbs wrote on Twitter: “Wowza!!!! I cannot believe Novak just patted the umpires foot!!!!!!!!!! I mean wowza !!! The rules are the rules, you have to get that serve off before 00. I mean there is leniency sometimes because of the point prior but wtf with touching the foot!???”

New York Times tennis writer Ben Rothenberg added: “He shouldn’t do that.”

Fans were also filthy.

But Djokovic doesn't believe he overstepped the mark.

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

"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.

"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."

Djokovic unhappy with umpire

Djokovic maintains the second violation wasn't necessary.

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

"The second one, it's just not necessary under the circumstances for a 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. It was a very important game.

"Obviously four-all, I broke his serve back, got myself back in the second set, then lost that game. He won the second set. That completely changed the momentum of the match."

En route to his 6-4 4-6 2-6 6-3 6-4 victory, Djokovic also took issue with the Rod Laver Arena crowd getting behind underdog Thiem, who had never won a grand slam.

Despite leading, Djokovic took aim at the fans during the first set when he felt his serves were interrupted by crowd.

"Shut the f*** up," he was heard saying.

with Yahoo Sports