Nick Kyrgios reignited his feud with Boris Becker during Wednesday's Australian Open tennis coverage.
The Australian called out Becker while commentating on Alexander Zverev's win over world No 2 Carlos Alcaraz.
While Kyrgios continues his rehabiliation from ongoing injury problems, he is trying his hand in the commentary box.
The argument he had with Becker on social media hadn't been brought up publicly until Wednesday's quarter-final.
Nick Kyrgios reignited his feud with Boris Becker during the Australian Open
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Eurosport commentator Nick Lester first brought Becker into conversation when discussing his compatriot Zverev.
Lester said: "[Zverev is] looking to reach a seventh Major semi-final in his career.
"If you put him side-by-side on some of the German greats he would actually surpass Michael Stich’s number tonight if he can win.
"Boris Becker still way out in front with his 18 Grand Slam semi-finals. You get on well with Boris, don’t you Nick?"
To which Kyrgios quickly replied: "Yeah me and Boris go way back. Way back."
Lester was keen to dig deeper into the feud, responding: "We enjoyed that exchange on social media a few weeks ago."
Kyrgios took a particular grievance to Becker's claim that he would be as successful in this era of tennis as he was during the height of his career.
Kyrgios took his cue from Lester and said: "I mean according to [Becker], Zverev has got no knowledge on tennis. Only Grand Slam champions do. Absurd statement."
The pair's feud first came about following an interview Kyrgios gave in December, where he criticised Becker's views on tennis eras.
He told The Athletic: "The game was so slow back then. I've watched Boris Becker and I'm not saying they weren't good in their time, but to say that they would be just as good now, it's absurd.
"A big serve back then was like 197 to 200 [km/h]. People like me, we serve 220 consistently, to corners. It's a whole different ball game.
"Serve and volley, to do it all the time now, you need to be serving 220, because if you serve anything less than 220, Djokovic eats you alive."
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Boris Becker responded to Nick Kyrgios on social media in December
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Becker clearly took objection to Kyrgios' comments and gave his response on X.
He wrote: "Nick makes a lot of noise about tennis lately!?! Why does he speak about a sport he apparently hates?
"Fact-check Nick has never won a major championship as a player or coach... so where is any credibility coming from?"
But Kyrgios was keen to have the last word and posted a few replies of his own.
Nick Kyrgios had the last laugh during his feud with Boris Becker
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The 28-year-old wrote: "One thing is for sure I'm not gonna be sitting here in 20-30 years time, claiming that I could compete and compare to the new kids on the block. It's definitely an ego thing.
"Also I mean I've beaten [Roger] Federer, [Rafael] Nadal, Djokovic, [Andy] Murray so I feel like I have a little credibility… but it doesn't take a rocket scientist to see that Novak would wipe the floor against you in your prime? Like it's not an attack. It's just facts."