Speaking to a US tennis podcast last month, Kyrgios described Djokovic as someone who has a "sick obsession" with being as popular as Swiss rival Roger Federer.

The 24-year-old made the comments during the Italian Open where he was defaulted from his second-round match with Norwegian Casper Ruud after hurling a chair on to the court.

During the podcast, Kyrgios also ripped into Rafael Nadal and the Spaniard's uncle Toni.

Despite that tantrum, Djokovic, who is preparing for Wimbleodon in the sweltering heat of a hardcourt complex in central Belgrade, expressed sympathy for the Australian.

"Honestly, I think that deep down he is not such a bad guy," Djokovic said.

"I don't know why Kyrgios says all these things. Whether he is seeking attention or has some other motive.

"He obviously wants to be sincere and transparent. It's the way he is, I respect that like I respect all other players on tour.

"He can say what he wants, I don't have a problem with it. Does he show me the same amount of respect that most other players do? No, he doesn't, but that's the way he communicates these days."

The world No.1 Djokovic revealed that the two were actually close to establishing a healthy relationship before the Australian turned on him.

"Before he unleashed this wave of criticisms against me, I actually met him off court during a US Open tournament, five years ago I think, and talked to him a bit," said Djokovic.

"It was at a time when everyone was on his case because of his antics.

"I offered help in the sense that I told him he could always come and talk to me if he needed to, because I faced similar situations and the same kind of criticism for my behaviour when I was younger.

"But something changed inside him from that point on.

"I'd never had that kind of problem with anyone else on tour but I am not losing any sleep over it. I don't understand why or what happened but I don't judge him."

AAP