Nick Kyrgios has made sensational claim that a coach and trainer associated with the Croatian No.1 doubles seeds Nikola Mektić and Mate Pavić had threatened him and doubles partner Thanasi Kokkinakis with violence after their upset win on Friday night at the Australian Open.

“Just letting you know after yesterday’s chop fest in doubles my opponents coach and trainer proceeded to threaten to fight in the players gym,” Kyrgios wrote on Twitter.

“Tennis is a soft soft sport all because I moved and hit them with a tennis ball.”

Fans had got behind the pair during the match, something that did not go down well with the Croatians.

And Kokkinakis likened the scene to a UFC bout.

“That was crazy!! Mans (sic) thought it was @ufc,” Kokkinakis tweeted.

Pavić and Mektić spoke to the media after Friday’s match and expressed their disgust with the crowd’s “loud” behaviour.