More: What Kyrgios can learn from Day and Spieth l Kokkinakis confronts Kyrgios l Kokkinakis almost in on-court dust-up l Kyrgios' epic sledge
As if there was ever any doubt, Kyrgios made himself world tennis’ public enemy No.1 last week with his “Kokkinakis banged your girlfriend” sledge directed at Stan Wawrinka.
The 20-year-old Canberra-product has copped it from all corners ever since, with even Kokkinakis saying “I made it pretty clear he can’t be doing that.”
But Federer’s criticism should come as a wake-up call for Kyrgios.
“I think we all agree that he crossed the line by a long shot,” the widely respected Federer said.
“We’re not used to that kind of talk in tennis. I know in other sports it’s quite common, maybe normal. Not in our sport, really.
“I think it’s normal that the tour comes down hard on him and explains to him that it’s not the way forward.”
Federer went on to describe the controversy as “not great for our sport, one that I think many players have tried to build up and make it a good image, build up as a good image.
“We want kids to be wanting to get into this sport because it’s a nice sport.”
Federer had previously been a notable Kyrgios supporter, backing the Aussie after a tumultuous Wimbledon tournament this year.
Kyrgios was fined $10,000 by the ATP after the outburst last week and has a potential second round match with Kokkinakis in Cincinnati this week.