Floyd Mayweather gets the better of Conor McGregor in mean-spirited New York press conference

In New York City, the witty barbs that characterised their exchanges Los Angeles and Toronto were replaced by what appeared to be real venom as the two men got personal

The Floyd Mayweather Jr. and Conor McGregor world media tour stormed into New York on Thursday with the fighters unleashing more profanity-laced attacks on each other as they looked to build up interest in their light middleweight boxing bout.

On the third stop of their four-day, four-city barnstorming blitz to promote their August 26 Las Vegas clash, the witty barbs that characterised their exchanges Los Angeles and Toronto were replaced by what appeared to be real venom.

UFC champion McGregor traded in the stylish suits he wore on the previous two legs of the tour for psychedelic pants and a furry white coat worn over a bare, tattooed chest.

He strutted imperiously onto the Barclays Center stage to an Irish ballad and thunderous applause before flexing his muscles, striking poses and rattling off a dance step or two as he waited for the undefeated boxer.

It looked for a moment as if the circus was going to take a turn for the worse when McGregor, who addressed the 40-year-old Mayweather as "boy" in Toronto, let a howling crowd know he did not take the charges of racism seriously.

“A lot of media have said I am against black people, that's absolutely ... ridiculous,” McGregor roared.

The Irishman, who at times during the earlier stops had appeared to get under Mayweather's skin, had no such luck in Brooklyn, where the American ignored the jibes and took selfies while McGregor barked in his ear.

McGregor is expected to be the aggressor in the ring against the former five-division world champion to make up for his lack of boxing experience and has played that role throughout the tour, which wraps up on Friday with a stop in London.

Famous for his knockout power in the MMA cage, McGregor managed only glancing blows on Thursday as Mayweather, widely regarded as one of the best defensive fighters of all-time, side-stepped and returned fired by dubbing McGregor a quitter.

Mayweather enjoyed the better of the verbal exchanges (Getty) (Getty Images)

“(He) didn't quit once, (he) didn't quit twice, (he) quit three time,” Mayweather screamed with another volley of profanity, referring to McGregor tapping out in his three career defeats.

While boxing purists have denounced the fight as nothing more than a laughable cashgrab it has nonetheless captured the fascination of many fight fans.

McGregor has been the undisputed favourite at each stop on the media tour, and can expect more of the same in London, but few give him any chance in the ring against one of the most skilled and tactically astute boxers of all time.

It didn't take long for things to get nasty (Getty) (Getty Images)

The fight would seem an outlandish mismatch with Mayweather 49-0 stepping into the ring against McGregor, who will be making his professional boxing debut.

The underdog role is one that fits McGregor like one of his tailored suits, however, and he recalled similar predictions before he beat Jose Aldo to win the UFC featherweight title in late 2015.

“They said the same things then as they're saying now,” he said.

Dana White was on hand to separate the two men (Getty) (Getty Images)

“They said I had no chance. They said I’m in over my head. They said he kicks too hard. Too many weapons.

“The Irishman is going to fall short, he doesn’t stand a hope.

“It took me 13 seconds.”