EVEN by boxing’s gaudy, attention-seeking standards, the promotional pre-fight clashes last week between Floyd Mayweather and Conor McGregor have been quite something. Mayweather, the retired, undefeated champion across five boxing divisions coming back for the paycheck to clear his tax bill, versus the mixed martial arts fighter from Dublin with the hammer left hand, profane mouth and indestructible ego. If the actual fight, under what used to be called Marquess of Queensbury Rules, lives up to the promotional hoopla it will be astonishing.

The Irishman turned up for the first media encounter with his rival dressed in a pinstripe suit – on closer inspection the stripes read, ‘F--- you’, in tiny lettering, all the way down his jacket and trousers.

There has also been an outcry over racism. Watching Mayweather shadow box on stage McGregor called out, “Dance for me, boy!” – a phrase which has overt racist connotations. Later, as he swaggered around on a stage, he told the assembled fans and journalists: "All of the media seem to be saying I'm against black people... Do they not know I'm half black? I'm half black from the belly button down."

The light-middleweight fight between Mayweather and McGregor takes place on August 26 in the T-Mobile arena on the Las Vegas Strip in Nevada. CBS Sports this week quoted Leonard Ellerbe, CEO of Mayweather Promotions, as saying that tickets for the fight will start at $500 and range up to $10,000. But the 'cheap' seats will be limited: the average price is, to no-one’s surprise, expected to cost thousands of dollars.

Given the venue’s listed capacity of 20,000, CBS reckons that an eight-figure gate could go along with a record pay-per-view rate to make it “potentially the biggest money-making combat sports event of all time”.

Mayweather, 40, is one of the greatest pound-for-pound fighters ever, retiring undefeated in 2015. He had been a world champion at five weights. In March he declared that he was willing to come out of retirement to take on McGregor, the biggest star in the Ultimate Fighting Championship (UFC) firmament. Owing the US tax authorities more than $29 million was the other spur

Referring to McGregor’s reputed demand for $100m for the fight, Mayweather sniped: “I’m tired of all this crying about money and saying you want to fight. You’re blowing smoke up everyone’s ass. If you want to fight, sign the paperwork”.

McGregor, who turned 29 on Friday, is the reigning UFC lightweight champion and former featherweight champion. He has never boxed professionally, but that has done nothing to dent his confidence. Not for nothing is he nicknamed ‘The Notorious’.

He was born in Dublin. In an interview with an Irish newspaper in 2015 he said that when he was young he was a football fan, “but more as a player than a watcher. I suppose if you pushed me I would say Manchester United, but that’s only because it gets passed down from generation to generation. I think just about everyone in Ireland is either a Liverpool or United fan”.

He said he is inspired by people “who are chasing the dream, who are undaunted, who defy the odds”. Muhammad Ali was a key influence on him, probably as much for his bravura as his noble arts. In martial arts it was Bruce Lee, while former UFC light heavyweight champion Chuck Liddell “was the MMA figure who convinced me that the UFC was where I wanted to be”.

His ultimate ambition, he added, was to fight at Dublin’s Croke Park as world champion, where Ali fought in July 1972. “It is my dream to bring my sport to the Irish people and to follow in Ali’s footsteps”, McGregor said. “That would be unbelievable”.

On the UFC website he says he started training for fighting when he was growing up, “to be able to defend myself in an unarmed combat situation”. UFC was dreamed up in 1993 by the William Morris talent agency, which also owns and markets Miss Universe, which it acquired two year ago from Donald Trump.

McGregor really made UFC fans sit up and take notice when he defeated Diego Brandão at a UFC Fight Night in Dublin almost exactly three years ago. “We’re here not to take part”, he declared afterwards. “We’re here to take over”.

That victory over Brandao came during an impressively long run of wins. In December 2015 he took just 13 seconds of the first round to defeat Jose Aldo Jr to seize the UFC lightweight title. MMA Fighting website described it as “one of the most stunning and electrifying finishes in the history of combat sports”.

"No power, just precision," said McGregor after the fight. "No speed, just timing. That's all it takes, especially when you have my left hand. Nothing can take that left hand."

As well his UFC titles the Dubliner has simultaneously held the Cage Warriors featherweight and lightweight championships. Last year Forbes magazine put him at number 85 in its list of the 100 highest paid athletes, noting that he had made a reported $22 million between his fight purses and his endorsements over the last year – $18m of it in UFC salary and fight earnings, and the rest in endorsements. (Mayweather was number 16, with $44m overall)

Two months ago his girlfriend, Dee Devlin, gave birth to their first child, Conor Jack McGregor.

The fighter’s rumbustious style, in and out of the ring, has been aided by his high social-media profile: he has 14.9 million followers on Instagram and 4.8m on Twitter. Earlier this week he tweeted a picture of him on New York’s Fifth Avenue – bare-chested, so that he could display his muscular and heavily tattooed torso.

“Whether you appreciate his style or consider him loud and excessive”, says McGregor’s UFC bio, “there’s no denying this about [him]: the UFC has seen nothing like him”.

But once all the shouting and grandstanding is over, will he have what it takes to win over an undefeated former world boxing champion? Whatever the result, no one will lose financially.