Floyd Mayweather Jr and Conor McGregor met face to face on Tuesday for the first time, at least publicly, as they kicked off a four-city, three-country international press tour to drum up interest in their 12-round super welterweight matchup on 26 August at T-Mobile Arena in Las Vegas.

Both men lived up – or down, depending on your perspective – to their reputations as two of the most profane, outspoken trash-talkers in all of sports. Yet their collective showmanship, a side course in most contexts, is as essential an ingredient as ever as they promote an event that’s not expected to offer much in the way of authentic competition.

It is, after all, a boxer widely considered the greatest of his generation against an opponent with no professional boxing experience. Regardless, the circus-like event is expected to generate hundreds of millions of dollars in revenue. The price point for the pay-per-view telecast was announced on Monday: $89.95 for the standard-definition telecast, $99.95 for HD.

McGregor, the two-division UFC champion from Dublin, was first on to the stage at the 21,000-seat home of the city’s pro basketball and hockey teams. He was dressed smartly in a pinstripe suit with a pink tie but he stood alone and exposed, as if he missed a cue. Surely, that was no accident. If the complete lack of UFC branding on the building wasn’t a clear enough signal: this was a Mayweather production.

Moments later, Mayweather entered from the back of the room surrounded by his linebacker-sized bodyguards and entourage. He took the stage in a star-spangled The Money Team jumper, one that McGregor was quick to zero in on when he finally had his turn with the microphone after a brief introduction from Dana White, who never appeared more like a fifth wheel given how the UFC has been marginalized from the promotion.

“He’s in a fucking track suit,” McGregor said to the delight of the crowd, before taking shots at Mayweather’s reported tax troubles. “He can’t even afford a suit anymore! The Rolls is a 2012 outside. He is fooked!”

Added McGregor: “There’s no other way about it. His little legs, his little core, his little head. I’m going to knock him out inside of four rounds, mark my words.

“The movement, the power, the ferociousness. He’s not experienced this. He’s fought people who have shied away from him. I don’t fear this limited set of fighting. This is a limited set of rules that makes this half a fight, a quarter of a fight. If this was a true fight, it wouldn’t even take one round. ... What can I say, I’m a young confident happy man that has worked extremely hard for this.”

Mayweather absorbed McGregor’s verbal jabs from his chair, arms crossed, looking almost bored and disinterested. It’s a disposition many expect he’ll reprise in the later rounds of their 26 August meeting in which he’s been installed as a better than 10-1 favorite, but he came alive when the microphone came his way.

After leading the crowd in his “hard work, dedication” mantra, Mayweather’s unleashed a profane tirade as he stalked back and forth across the stage with the energy of a revivalist preacher.

“You line ‘em up and I knock ‘em down like bowling pins,” he said. “On August 26th, I’m gonna knock this bitch out too.”

McGregor fired back from the side – “You haven’t knocked anyone out in about 20 years!” – but only those watching from close range could hear it. Of course, his microphone had been switched off, undercutting the chances of the back-and-forth dialogue many had turned out for.

“Dance for me, boy!” cried McGregor at one point. “Dance for me, son!”

Mayweather ignored the thinly veiled race-baiting, calling for an assistant to bring over a backpack from which he pulled out a $100m check – ostensibly his payday from his 2015 blockbuster fight with Manny Pacquiao.

“Give me that backpack!” Floyd shouts to an assistant, before pulling out a $100m check from his last fight.

“He look good for for a seven-figure fighter, he look good for an eight-figure fighter,” Mayweather yelled to the crowd. “But motherfucker, I’m a nine figure fighter. This bitch made three million dollars his last fight. But we know that’s training camp money for me.”

McGregor fired back from his chair, saying that Mayweather should give the money to the US government.

“You right, I’m the IRS,” Mayweather said, prepared for the line of attack. “I’m gonna tax your ass.”

He continued: “I’m an old man. I’m not the same fighter I was 20 years ago, I’m not the same fighter I was 10 years ago, I’m not the same fighter I was five years ago, heck, I’m not the same fighter I was two years ago, but I can beat you.”

“We knew I was the A-side,” Mayweather said. “That’s why it says Mayweather first. That’s why this bitch had to come to the boxing ring.”

The American then took aim at McGregor’s three career losses by submission.

“We know Mr Tapout like to quit and you will,” Mayweather said. “You going out on your face or you going out on your back. Which way you want to go? Which way do you wanna go?

McGregor paused for a beat, saying nothing. A tactical mistake.

“That’s right, be quiet you little bitch.”

Eventually, the fighters came together for the traditional staredown. Dana White was forced, it seemed, to separate them.

Mayweather’s manager, Leonard Ellerbe, said attendance for the press conference was 11,000. The same routine will be repeated as the world promotional tour chugs on: Toronto on Wednesday, New York City on Thursday, London on Friday.