Nick Kyrgios has thrown the latest barb in his war of words with Alexander Zverev at the Australian Open.
Zverev kicked things off last week when he said some of the other young players were "just better" than Kyrgios, who provocatively dropped and did push-ups when the World No.7 served double faults during Germany's clash with Australia at the ATP Cup.
Kyrgios later dismissed the criticism, saying he wasn’t too concerned about what Zverev had to say.
“I'm not going to entertain that too much. With everything going on, that's the least of my worries,” the Aussie said.
However it appears as though Kyrgios may have been more offended than he originally let on.
Kyrgios levelled a cutting sledge at Zverev on Tuesday night in a since-deleted tweet.
After Zverev failed miserably while attempting Kyrgios’ signature ‘tweener’, the Australian Open’s official Twitter account invited Kyrgios to dish out some tips.
To which Kyrgios replied: “I agree, lots of better tennis players than me, but if you hit tweeners like his, please shush.”
Kyrgios and Zverev at odds?
"He's a great player. I'm not quite sure where those comments come from,” Kyrgios had said about Zverev’s barb.
“I'm sure he didn't mean them in a bad way. But if he did, then I'm sorry for whatever I've done to you."
Zverev told media in Melbourne that "there's a lot of young guys that are right now, no offence, just better than (Kyrgios).
"I think Stefanos (Tsitsipas) is better than him. Just simply because he is better over five sets and that's what you need as well."
Kyrgios cruised to a surprisingly drama-free first round win on Tuesday, downing Italian Lorenzo Sonego 6-2 7-6 (7-3) 7-6 (7-1).
Despite appearing at ease during the match, Kyrgios admitted being edgy as he took to the court, particularly given the focus on the Australian bushfires and his involvement in raising funds, saying he was playing "for a lot of people".
"Just with everything going on, walking out there, I was a lot more nervous than I have been in previous matches," he said.
"Australian Open, I usually feel pretty comfortable.
"The crowd was unbelievable. I got comfortable quite early in the match. I played an unbelievable first set, which helped. I thought the pressure kind of eased off after I won that first set (but) he didn't go away."
Zverev also reached the second round with ease, before pledging to donate his prize money to the bushfire appeal if he wins the tournament.