For two ridiculous rounds at least, it looked as though the freak show was going to have a suitably freakish conclusion. Conor McGregor, a man who had never boxed professionally before in his life, had taken the fight to Floyd Mayweather and was briefly — incomprehensibly — ahead on points.

A record-breaking television audience watching from around the world, not to mention the thousands of fans who had paid increasingly outlandish sums to take up a seat in the Arena, all began to ask themselves the exact same question: can he do it?

We all knew the answer. We knew it all along — no, of course he couldn’t. The facts are these: in the most lucrative fight in the history of combat sports, a man bearing a professional record of 49-0 and a reputation as one of the greatest boxers to have ever lived defeated a novice, a man with no prior boxing experience who was making his professional debut.

Was it exciting? Certainly, as for long periods the contest appeared to abandon the concept of the Queensbury Rules entirely. But in the end, sense prevailed. Having gamely conserved his energy through the opening few rounds, Mayweather sprung into life, obliterating McGregor’s non-existent defence and winning by way of TKO in the tenth round.

After a delay that Showtime blamed on “scattered outages from various cable and satellite provides and the online offering,” the two men appeared to equally mixed receptions, with the Irish invasion that McGregor had promised not quite materialising in the plush T-Mobile Arena, where even the cheapest seats ran into the thousands of dollars.

The fight was so novel that Hall of Fame referee Robert Byrd even had to give a lengthy lecture ahead of the first bell, sternly warning both men (although looking directly into the eyes of McGregor) that he expected them to act like “world championship winning professionals” and demanding “a clean fight”.

It didn’t take long for McGregor to show that he meant business. Yes, it took him just a matter of seconds to stand with his gloves clasped behind his back — Roy Jones Jr style — but he also worked the jab well, and caught Mayweather flush with a vicious uppercut that briefly startled the undefeated pro. He wasn’t just joking around; he was here to fight.

Mayweather appeared genuinely surprised that the question everybody had spent the past two months fervently debating — that being, would McGregor be able to land his shots — was answered so quickly and so comprehensively. More: McGregor's arsenal included more than just his notorious left-hand counter. He also worked the body well and landed several well-timed uppercuts.

Mayweather was also struggling to deal with McGregor’s noticeable weight advantage. The Irishman had promised that he would enter this fight at something close to 170lbs. He wasn’t kidding.

But that extra weight ultimately proved to be McGregor’s undoing, as he began panting heavily as early as the fourth round, when Mayweather grew into the contest and landed a straight right that forced McGregor to respect his punching power.

Having lost the first three rounds he picked up the next two, with the fifth ending in a moment of pantomime when Mayweather pushed away McGregor upon the sound of the bell for daring to mutter an insult in his direction. Byrd split them up, choosing to direct his ire towards the Irishman instead of the American.

Stung, Mayweather upped the ante. His jab repeatedly began to pass McGregor’s slack guard and, rattled, the mixed martial artist briefly reeled back. Mayweather sensed a first stoppage since 2011 and kept on the front foot, attacking and walking his opponent down. 

McGregor’s admirable aggression at the very start of the fight had cost him. Having picked his opponent off for a couple of rounds, Mayweather went to work in the ninth, landing several punishing shots and somehow failing to land a knockdown before the bell rang. McGregor practically collapsed into his corner at the sound of the bell. A minute later and he was still not ready to resume.

Mayweather’s final flurry was vicious. A straight-right stunned McGregor and left him staggering backwards, with Byrd diving in to wave off the contest after two more shots to the head landed.

What next? Mayweather insisted this week that this is it, and that his second retirement from the sport will be more permanent than the first. “I’ve promised my children and I've promised the people around me that this is the last one,” he said. “You know that when you push your body to the limit and beaten everyone out there that now the time has come.”

Having topped Rocky Marciano’s professional record in his final fight, there is precious little reason for him to return. As for McGregor, the gamble failed to pay off. In Vegas the unobtainable is never more than a roll of the dice away, but as expected, the luck of the Irish eluded the man from Crumlin on the biggest night of his professional career. He is far from the first man to lose in Las Vegas. 

Or did he? McGregor remains the face of the UFC. He remains the biggest star in the rapidly growing sport of mixed martial arts. And — to quote an oft-repeated line from the controversial press tour to promote this fight — he has “quadrupled my net worth in one half a fight”.

No, both men emerge from this contest as winners, even if the history books will chalk this up as a victory only for Mayweather. If there were any losers, they were stood outside the ring peering in, rather than fighting in the middle of it. But then we already knew that, didn't we?