NICK Kyrgios has taken his bad boy antics to a new level, delivering a stunning on-court sledge to Stan Wawrinka by telling the Swiss star fellow Australian player Thanasi Kokkinakis slept with his girlfriend.

Shortly after losing the first set in Thursday’s match at the Montreal Masters, Kyrgios was heard delivering this scathing comment to the two-time grand slam winner and world No.5: “Kokkinakis banged your girlfriend, sorry to tell you that mate.”

It is believed Kyrgios’ comment was is in reference to 19-year-old Croatian player Donna Vekic, whom both Wawrinka and Kokkinakis have been linked to.

WATCH KYRGIOS’ TWO INCREDIBLE WAWRINKA SLEDGES IN THE VIDEOS

An angry Wawrinka fired back on Twitter after the match, calling for the ATP tour to take action against the Aussie - which it ultimately did in the form of a maximum $US10,000 fine.

“So disappointing to see a fellow athlete and colleague be so disrespectful in a way I could never even imagine,” he tweeted.

“What was said I wouldn’t say to my worst enemy. To stop so low is not only unacceptable but also beyond belief.

“There is no need for this kind of behaviour on or off the court and I hope the governing body of this sport does not stand for this and stands for the integrity of this sport that we have worked so hard to build.”

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media_camera Thanasi Kokkinakis playing doubles with Donna Vekic at last year’s Australian Open.

Asked about the comment in a post-match interview Kyrgios said: “He (Wawrinka) was getting a bit lippy with me, kind of in the heat of the moment. I don’t know, I just said it.”

Kyrgios and Wawrinka exchanged words in the point before the sledge and the Aussie was also upset at the performance of a line judge.

Wawrinka fired back, saying he had confronted the Aussie about the sledge in the locker room.

“He tried to avoid me, but I confronted him,” said Wawrinka.

“I just hope that the ATP will take big measures against him because he’s young maybe, but there’s no excuse.

“Every match he has problems. Every match he behaves very badly.

“On top of that the problem is that he doesn’t just behave badly towards himself he behaves very badly towards the people around: the other players, the ball kids, the umpires.

“I really hope the ATP will take major action against him this time.”

Kyrgios went on to win the second set and then the match after Wawrinka retired with a back injury while trailing 4-0 in the final set.

media_camera Nick Kyrgios hits a return against Stan Wawrinka in Montreal.

Wawrinka separated from his wife Ilham Vuilloud in April this year, announcing it on Facebook. He was subsequently linked to Vekic and she was in the crowd watching some of his matches at Wimbledon.

Kyrgios’ comment drew a furious response from Wawrinka’s coach, former player Magnus Norman, who described it as “really low. Hope for you that you have people around that will teach you a thing or two about life tonight. Very bad.”

media_camera Donna Vekic (left) watches Stan Wawrinka’s clash with Fernando Verdasco at Wimbledon.

Wawrinka blew up at the French Open this year when the tournament’s official website made reference to his personal issues.

The French Open piece read: “If Stan can overcome the constant reminders of his muddied personal waters, then maybe he will enjoy a run to the semis, where he is slated to meet his Davis Cup buddy Federer. And that would give Rog a chance to pass on a few tips on how to juggle personal and private lives.’

media_camera Croatian tennis player Donna Vekic.

Wawrinka was angered, calling it a “completely stupid article.”

“It’s the official website of a grand slam, so I hope the guy who did that article is not a journalist. I also hope the guy who is supposed to check all the articles on the website is not working anymore for the tournament. Because for me, for a grand slam website, it should be an article about the tennis and that’s it.

media_camera Stan Wawrinka, of Switzerland, returns to Nick Kyrgios, of Australia, at the Rogers Cup tennis tournament Wednesday, Aug. 12, 2015, in Montreal. (Paul Chiasson/The Canadian Press via AP)

“I saw the article last night. I told the tournament that I wasn’t really happy about it, and I don’t think it was great for the tournament to do that s*** article. That’s it. But after that, you know, I’m here to play tennis and to focus on my game. I can put that on the side, and that’s it.”

Kyrgios’ Davis Cup teammate Kokkinakis was linked to Vekic in 2013 but laughed off claims they were an item. The pair played doubles together last year.

It’s not the first sign of bad blood between Kyrgios and Wawrinka.

The Swiss star raised eyebrows at a press conference shortly after his 49-minute dismantling of Kyrgios at the Queen’s Club in June.

After Kyrgios complained of being “sick for the last week” and stated he “didn`t want to be there”, Wawrinka said he was not surprised.

“I think he’s saying a lot of things every day, so it’s quite interesting for journalists to hear that,” Wawrinka said.



“It doesn’t really surprise me. When I read his interview, it’s always funny, a lot of things you can take. I read before the match he was ready, excited for the challenge, and now he was sick.

“So I’m just saying he says a lot of things, and I think it’s always interesting as a player to read what he’s saying and how his mind working.

“I’m sure he will be ready for Wimbledon, because if he switches off two weeks of tennis, then he can go home and not play Wimbledon.

“He’s really talented player. He already beat some top players, made quarters in Wimbledon. He’s the future of tennis.”

media_camera Nick Kyrgios and Lleyton Hewitt playing doubles at the Rogers Cup in Canada.

The controversy in Canada continues a dramatic year for 20-year-old Kyrgios.

He attracted widespread criticism for his on-court behaviour at Wimbledon, where he reached the fourth round and was accused of tanking in his loss to Richard Gasquet.

The world No. 41 announced this week he is now working alongside Australia’s double grand slam winner Lleyton Hewitt in an informal capacity, a move that was widely applauded.

Kyrgios will meet American John Isner in the round of 16 in Montreal on Friday.

Originally published as Kyrgios’ jaw-dropping girlfriend sledge