Nick Kyrgios has called Novak Djokovic a "strange cat" as their feud continued on the opening day of the Australian Open.

Djokovic had said on Sunday that he had no respect for Kyrgios off the court after the Australian had been critical of the world number one's actions during the coronavirus pandemic.

Kyrgios spoke out against the ill-fated exhibition event that Djokovic organised in the summer which observed no social distancing and saw a number of the players contract Covid-19 after partying at a nightclub and again spoke out against the Serbian for making a list of requests for players who were stuck in quarantine.

Both men got their Australian Open campaigns off to a winning start as Djokovic beat Jeremy Chardy in straight sets and Kyrgios got the better of Frederico Ferreira Silva.

And Kyrgios continued the war of words in his post-match press conference.

"It's a strange one for me, because, you know, I read his comments, he said he doesn't respect me off the court," he said.

"It actually would make complete sense to me if he was like, 'Look, I don't respect the guy on the court', because I understand if he doesn't agree with some of my antics on the court that I have done in the past. And when we've played matches I think I've actually been pretty good towards him.

"But I'm not quite sure how he can't respect me off the court. I feel like I've gone about things extremely well, especially during the pandemic. I was driving around delivering food to people during the pandemic that didn't or couldn't get the supplies.

"I was extremely careful about what I was doing. I didn't want to spread the virus to anyone.

"Now I'm actually trying to donate meal kits to people that need food. I have my foundation. So it's very strange to me as why he would say he doesn't respect me off the court. I actually do a lot off the court.

"But he's a very strange cat, Novak is. Heck of a tennis player, but unfortunately someone that's partying with his shirt off during a global pandemic, I don't know if I can take any slack from that man. That's as bad as it gets for me."

Djokovic was offered the chance of another reply in his press call, but chose not to respond.

He said: "You can read (what he said), but I'm not going to answer to anything."