London - Nick Kyrgios slammed Marion Bartoli after the former Wimbledon champion labelled the controversial Australian "pathetic" and accused him of squandering his talent.
Bartoli, who won Wimbledon five years ago, claimed Kyrgios and France's Gael Monfils were wasting their huge potential because of bad attitudes.
Kyrgios has been in trouble for his immature behaviour on and off the court several times in his short career.
In a stinging blast, the Frenchwoman said Kyrgios's work ethic was "just not good enough to win a grand slam", and said it was "pathetic" to see the 23-year-old and Monfils failing to apply themselves in the right way.
"It seems like they can't grow up, they can't become men and they can't take charge of their own lives," Bartoli said.
"I truly hope Nick will be able to get it together at some point. I don't know what he needs. He's going to waste his life if he keeps on acting like that."
Kyrgios, who faces Japan's Kei Nishikori in the Wimbledon third round on Saturday, gave a furious response to Bartoli's jibes, defending himself and Monfils, who reached the fourth round on Friday.
"Yesterday @bartolimarion had to say some nice things about @iamgaelmonfils and myself.. They're 'Pathetic' 'Children' They 'Can't become men' 'wasting their life' - Who are you to judge the way we go about things?" Kyrgios wrote on Instagram.
"Who are you to tell us how to do things, when u have no idea what we've been through?.... stop assuming you know what's best for others when you think you've had a little success.
"We get it, we know you have to remain relevant, but I'll give you a heads up, we don't care what you have to say."
Monfils also made clear his disdain for Bartoli when asked about her comments following his Centre Court win over Sam Querrey.
"It's easy to criticise people when you don't know them. So I won't even pay any attention," he said.