Stan Wawrinka has slammed Nick Kyrgios and called for disciplinary action to be taken after the controversial Australian tennis star sledged him during their second-round clash at the Montreal Masters.

In a comment picked up by a courtside microphone, Kyrgios, 20, linked the reigning Australian and French Open champion with teenaged Australian player, Thanasi Kokkinakis.

“Kokkinakis banged your girlfriend. Sorry to tell you that mate,” said Kyrgios midway through the second set.

Wawrinka divorced his wife Ilham earlier this year and has since been romantically associated with 19-year-old Croatian player Donna Vekic.

Kyrgios went on to win the second-round match in Montreal 6-7 (8-10) 6-3 4-0 after the third-seeded Wawrinka retired due to a back injury in the deciding set.

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

“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.”

Kyrgios will play American John Isner in the third round of the US Open lead-up event.