Nick Kyrgios has again questioned the ATP Tour’s consistency after world No.2 Novak Djokovic apparently escaped with a fine after hitting a spectator with a tennis ball.

“I would’ve been defaulted and suspended until 2025,” Kyrgios half-joked on Twitter.

Djokovic’s temper got the better of him twice in his 6-3 5-7 6-4 victory over Andy Murray on Saturday night to retain the Qatar Open title, causing umpire Carlos Bernardes to hand him two warnings, including the loss of a point on the second warning. 

For those who did not see, here is the moment where Nole picked up a warning in set one. #ATP pic.twitter.com/pYB7g3fBzn

— TennisNow (@Tennis_Now) January 7, 2017

I would've been defaulted and suspended until 2025 😂 https://t.co/HsIoG9IOAL

— Nicholas Kyrgios (@NickKyrgios) January 8, 2017

The first came in the sixth game of the first set when Djokovic, annoyed after losing a point, slapped a ball into the crowd on the bounce, hitting a woman.

He was later warned again and docked a point after smashing his racquet in frustration during the second set.

It was the first incident that drew comment from Kyrgios, who recently completed a three-week suspension for “tanking” after not giving full effort in a match at the Shanghai Masters, where he was also fined heavily.

Kyrgios and Djokovic have history when it comes to sniping at each other over on-court behaviour.

At the French Open last May, umpire Carlos Ramos gave Kyrgios a code violation for yelling “towel” at a ball boy, which prompted the Australian to accuse the veteran official of double standards.

In the heated exchange, Kyrgios referred to Djokovic’s unpunished act of pushing an umpire’s arm in Rome earlier that month.

Kyrgios said on-court: “So when Djokovic pushes an umpire that’s all right?”

When Djokovic was asked about his take on the incident he replied: “I’m not getting into it. It’s completely his choice what he’s going to do about that. So, you know, by mentioning my name, I don’t think it was necessary, but again, I’ve got to respect his choice.”

Nick Kyrgios has raised apparent double standards before. Photo: AP

When asked about the so-called double standards between top players and challengers, Kyrgios said: “I think we all know in this room if that was me that did that (pushed an umpire), it would be an absolute circus.

“But if he did it, you know, nothing really happened of it. It speaks for itself.”

Djokovic said hitting the spectator with the ball on Saturday night was an accident but admitted he may have got off lightly.

“I definitely didn’t want to hit the ball at anybody,” Djokovic said. “Just happened. Fortunate not to get a bigger fine. I have to be more careful I guess. I accept that I made a mistake.”

– with AAP