Australian star Nick Kyrgios told Mats Wilander to "shut up" and that nobody cares what he thinks after the seven-time major winner controversially told Andy Murray to retire from tennis.
Former world number one Murray slumped to his joint-worst defeat at a Grand Slam on Sunday with a 6-1, 6-3, 6-2 loss at the hands of Stan Wawrinka in the first round of Roland Garros.
"I worry about Andy Murray. I would love to hear him say why he is out there, giving us a false sense of hope that he going to come back one day," Wilander told Eurosport.
"I keep getting a little bit disappointed, is it his right to be out there doing that? Why? I did it and I shouldn't have, it was the biggest mistake I did in my career. I think Andy Murray needs to stop thinking of himself and start thinking about who he was. Does he have a right to be out there taking wildcards from the young players?"
Kyrgios, no stranger to taking potshots at some of the sport's biggest names, leapt to the defence of 33-year-old Murray who needed a wildcard to play his first clay court tournament in three years.
"Just read what Wilander said about @andy_murray .... shut up Mats, no one cares," tweeted Kyrgios.
"Muzz, just know that how ever long you stay, we all appreciate and enjoy your tennis and banter. Also I've never watched a point of Mats Wilander."
Murray, a three-time Grand Slam title winner and runner-up at the French Open in 2016, has undergone two hip surgeries in order to cure an injury which pushed him to the brink of retirement.
After his loss to Wawrinka - his first opening round defeat in Paris since his 2006 debut - Murray insisted he intends to keep playing even though his ranking is now 111.
Murray also found support from former coach Daniel Vallverdu who coached him from 2010-2014.
"He's entitled to his opinion. Like I'm entitled to mine to think that's absolutely PATHETIC from Mats...," tweeted Vallverdu who is now the coach of Wawrinka.