Nick Kyrgios has apologised after being fined for an insulting remark to Stan Wawrinka during their Rogers Cup match this week.
French Open champion Wawrinka branded Kyrgios "unacceptable" and called for action to be taken against him after the Australian appeared to make comments about his girlfriend during Wednesday's match in Montreal.
On-court microphones recorded 20-year-old Kyrgios walking to the net and saying: "Kokkinakis banged your girlfriend. Sorry to tell you that mate" - an apparent reference to Australian Davis Cup team-mate Thanasi Kokkinakis.
The woman in question is reported to be 19-year-old Croatian player Donna Vekic, who has been linked to Wawrinka since he divorced his wife Ilham in April. Vekic was in the crowd to watch the Swiss' Wimbledon third-round win over Fernando Verdasco last month.
Speaking on court after the exchange, Kyrgios claimed he had been provoked, saying: "He was getting a bit lippy with me. Kind of in the heat of the moment, I don't know. I just said it."
However, the ATP fined the Australian for the remark - and hours later he apologised.
So disappointing to see a fellow athlete and colleague be so disrespectful in a way I could never even imagine.
— Stanislas Wawrinka (@stanwawrinka) August 13, 2015
Kyrgios said on Facebook: "I would like to take this opportunity to apologise for the comments I made during the match last night vs Stan Wawrinka.
"My comments were made in the heat of the moment and were unacceptable on many levels. In addition to the private apology I've made, I would like to make a public apology as well. I take full responsibility for my actions and regret what happened."
The Australian won the contest after his opponent retired hurt - and Wawrinka tweeted afterwards: "So disappointing to see a fellow athlete and colleague be so disrespectful in a way I could never even imagine.
"What was said I wouldn't say to my worst enemy. To stoop 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 up for the integrity of this sport that we have worked so hard to build."
Controversy has followed Kyrgios around since his 2014 breakthrough when he knocked Rafael Nadal out of Wimbledon.
At this year's tournament he was moved to deny accusations of abusing an umpire and throwing a game, while on Davis Cup duty with his country he shouted "I don't want to be here" while on court.
