Floyd Mayweather Jr., front left, came out in an Irish flag and then threw money around Thursday at Barclays Center in Brooklyn. Conor McGregor, right, wore a coat he claimed was made from polar bear fur. (Frank Franklin II/Associated Press)

Conor McGregor, the Dublin-born mixed martial arts superstar, strutted to the stage at Barclays Center, his chin jutting out and leading the way, his chest bare beneath a white fur coat. He was followed by Floyd Mayweather Jr., who had an Irish flag draped over his shoulders despite no known Irish ancestry.

And in short order, they were off, insulting each other’s looks, talents and bank accounts. McGregor, 28, bragged about money, and Mayweather threw piles of it in the air. In the third round of the scheduled four-round battle — the combatants relying on flapping lips rather than flying fists — the two fighters aimed to land clean shots, but both stayed relatively dirty.

“I don’t just smell victory. You know what I smell? I smell a [expletive]!” Mayweather, 40, barked at McGregor at one point.

While many fight fans might expect the Aug. 26 bout itself to be dull — a novice boxer pitted against one of the best tacticians ever to lace up gloves — this week’s media tour has been a championship-caliber spectacle — ridiculous, absurd, juvenile and at times entertaining. Both men are among the most outspoken, cocky competitors their respective sports have seen, a pair of blood-thirsty, camera-hungry peacocks.

“When we were talking about this fight, the one thing everybody said is ‘You can imagine how exciting the press conferences will be,’ ” said Dana White, UFC’s president.

The talking tour is hitting four cities in four days, from Los Angeles to London — with each stop showcasing plenty of showmanship and very little sportsmanship. Both fighters played their roles, trying to sell tickets and inject excitement into a bout that would be considered more of an exhibition or sideshow had the participants been lesser names.

While the fight itself might settle only bar stool debates, the week’s media tour is intended to fan the flames. The fighters’ animosity, real or forced, is designed to sell tickets — priced $500 to $10,000 — and bait the public into plopping down $90 or $100 for the pay-per-view. The fight already had plenty of intrigue, and the week’s festivities are doing little to quell the buzz. Thousands have showed up in each city to watch the fighters strut and crow. White said the UFC’s Facebook page registered 12 million viewers for the first news conference alone.

“The numbers are astronomical,” he said.

The two men had never met face to face before Tuesday’s event in Los Angeles. Promoters say their feelings were quick to develop and even quicker to spoil.

“It gets worse every city we go to,” White said.

The show-before-the-show has been akin to a raucous touring circus with expletives and insults flying, with both fighters eager to engage in schoolyard heckling.

“Some points it became a little bit uncomfortable,” said Stephen Espinoza, the executive vice president for Showtime Sports. “. . . If you know anything about the two guys, this isn’t WWE. It’s not family-friendly. Do I condone all of the language? No. But at the same time, this is combat sports. Tempers are flaring.”

Again on Thursday night in Brooklyn, neither fighter worried about children’s ears among the 13,165 in attendance. Mayweather called McGregor a con artist, a circus clown and a quitter — with many expletives sprinkled in. McGregor called Mayweather a squirt who wears high heels — with many expletives sprinkled in.

Both fighters this week guaranteed a knockout, and in addition to the R-rated taunting, Mayweather has brought out props, hoisting a $100 million check in Los Angeles and grabbing an Irish flag from the crowd in Toronto. McGregor has sported a suit with small-print expletives serving as pinstripes and swiped Mayweather’s pricey handbag on stage. He said his white fur coat was made of polar bear.

“I don’t give a [hoot] how hot it is outside,” he said. “I’m still wearing this.”

Out of the gate, though, the two fighters made clear that this bout isn’t really about animosity or grudges. The two had an awkward back and forth in Los Angeles on Tuesday, setting the stage for the ensuing stops. As he was in Toronto and New York, McGregor was clearly the Staples Center favorite.

“You want me to give it to him right now?” Mayweather barked to the crowd, which paid nothing to get in and cheered wildly. The boxer, a five-division champion with a 49-0 record, smiled. “We gonna save that for the payday,” he said. “We’re gonna save that for the money.”

While McGregor also seems to thrive on the attention and the pageantry, he’s aware that he has little to lose. His legacy as an MMA great is unlikely to be impacted significantly by stepping in with one of the best boxers ever. His bank account, however, will be life-changing; he will stand to earn many times more than what he would make on the biggest UFC card. He alluded to this talking about his newborn son. “My little boy,” he said, “to provide for him and to set him up for life, what more motivation could you need?”

Indeed, both fighters figure to bring in eight- and possibly nine-figure paychecks from a single night of work that could support generations of progeny, assuming some degree of fiscal responsibility.

“That’s a $3 million fighter. This is an $800 million fighter,” Mayweather shouted at one point Thursday night. “I ain’t running nowhere but to the bank.”

Even if it’s a cash-grab and even if fight experts have been critical of the matchup — with most discounting McGregor’s chances in his boxing debut — no one involved with the event is offering any apologies.

“This is bigger than one person having an opinion,” said Leonard Ellerbe, the chief executive of Mayweather Promotions. “. . . This is a big event that the fans have demanded. The fans want it.”