Recently-retired Floyd Mayweather Jnr was provoked into a shouting match over Gennady Golovkin by a heckler in New York City, according to TMZ.
The 40-year-old briefly came out of retirement in late August to beat Conor McGregor, seeing off the Irishman in the 10th round of the bout in Las Vegas.
Maywather, who had attended the New York Knicks basketball fixture, was accused by the heckler of "running away" from Kazakh fighter Golovkin.
By defeating McGregor, Mayweather secured a 50-0 unbeaten record as a professional, but exchanged a war of words with the heckler on Monday night.
Defending himself from the tirade of verbal insults, Mayweather reportedly claimed that he wasn't afraid of Golovkin.
In a video obtained by the TMZ News Agency, Mayweather dismissed the claim against him, before he reiterated that he is happily retired for good from the sport.
In an interview broadcast in May, Mayweather expressed that he believes Golovkin would be that of an easy opponent in the ring, even at the age of 40.
Mayweather said: "Kell Brook fights GGG and you guys were crazy about GGG, talking, 'GGG was such an unbelievable fighter.' He's OK. I mean, straight up and down, no special effects. Even at the age of 40, I am not looking forward to fighting Triple G, but that would be easy."
Watch the video provided by TMZ's YouTube account below.
Golovkin and his camp had previously said that a fight against Mayweather would be of interest to them, however, it seems unlikely that such an event would go ahead.
His willingness to arrange a big-money bout could perhaps entice Mayweather, who of course does have history of coming out of retirement.
Golovkin said: "Right now this is the biggest fight in the world. He's a great champion. Look at me, I'm not big, I'm not fat. My couple of last fights - I was 158, 159. It's possible for me [to go down to fight him]. I would go to 154 just for Floyd.
"I understand that this is biggest fight in the world. This would show who is who, the best fighter in the world."