Nick Kyrgios has been vigorously booed by spectators during his first time back on court after his controversial sledge towards opponent Stan Wawrinka.
In a video posted to Vine, loud boos can be heard as Kyrgios sits down courtside before his third-round match against No.16 seed John Isner.
During a second-round Rogers Cup match in Montreal on Wednesday, Kyrgios, 20, linked the reigning Australian and French Open champion with teenage 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 linked with Croatian teenager Donna Vekic.
The world No.5 appeared to not hear the comment at the time, but unleashed after the match, won by Kyrgios 6-7 (8-10) 6-3 4-0 after Wawrinka retired with a back injury.
"He's young but that's no excuse ... every match, he behaves very badly," Wawrinka told reporters in French.
"The problem is he doesn't just behave badly towards himself, he behaves 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."
Wawrinka's call was answered by the tennis association with Nick Kyrgios fined $US10,000 ($A13,550).
"The ATP has announced that Nick Kyrgios has been fined the maximum on-site amount of $10,000 for an insulting comment he made to Stan Wawrinka during their second-round match at the Rogers Cup in Montreal, Canada," a statement from the association said.
It added that "additional penalties may be forthcoming", as the ATP was still reviewing the matter.
Shortly after the release of the ATP statement, Kyrgios made a public apology 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."
Novak Djokovic racked up his 50th win of 2015 to reach the quarter-finals of the Montreal Masters and then blasted Nick Kyrgios for the crude sexual slur at Stan Wawrinka which has rocked the sport.
Djokovic lashed out at Kyrgios who was fined $US10,000 (NZD$15,200) for an obscene sexual remark made in Wednesday's third round.
On-court microphones picked up the remark made by the 20-year-old Australian concerning Wawrinka's girlfriend.
Djokovic, a close friend of Wawrinka, said Kyrgios deserved to be punished.
"Some players have problems to control themselves on the court. Sometimes when you go through the emotional challenges, it slips out of your mouth," said the top seed.
"But again, there's no excuse for what he has said."
Wawrinka, who separated from his wife earlier this year and has been linked to Croatian tour player Donna Vekic, said the ATP should take "major action this time".
As well as the maximum $10,000 on-site fine, the ATP said they could not rule out further sanctions.
"He was fined, he deserved it," added Djokovic.
"I think he's going to learn a lesson in a hard way. Hopefully this won't happen to him anymore.
"I understand that every player goes through certain tantrums, emotional ups and downs during the match. In a big fight and at this level, I understand.
"But it's not, I would say, fair, and there's no excuse of directing your tantrums to your opponent, especially to somebody that is not even there."
AFP
