Stanislas Wawrinka has called on tennis's governing body to punish Nick Kyrgios after the Australian told the two-time Grand Slam champion that another player had "banged" his girlfriend.
The two were competing against one another in the second round of the Rogers Cup, and between points, 20-year-old Kyrgios said to Wawrinka that Thanasi Kokkinakis had slept with his partner.
The French Open champion did not react to the remark during the match, from which he was forced to retire in the third set due to injury, but the Swiss pro has now taken to Twitter to express his fury.
The 30-year-old tweeted: "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 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 up for the integrity of this sport that we have worked so hard to build."
Watch Kyrgios make the comment in the Vine below: