Though it should have known better, New York-New York is not prepared for the Irish.
At 2 a.m., it asks everyone to leave the ersatz pub tucked in alongside the casino floor. It's called Nine Fine Irishmen. These people are not creative thinkers.
At 2:15, the casino asks again. No one moves. It's a young crowd, most of them men in too-tight printed shirts, all of them epically hammered. Even the hookers are drunk.
One guy staggers up and begins a long monologue about, well, it's hard to say because he can no longer form words. The joint is so crammed that everyone is holding everyone else up.
At 2:30, the staff turn up the lights. By 2:45, they bring in security to push the crowd outside. That turns it into a run on the nearest open bar in sight – a circular job in the centre of the casino. That's not metaphoric. They run.
Even by Vegas standards, it's late. There's only one bartender there. He gets a "Why me?" look as the gang crashes against the bar top. For the next half hour, it's pandemonium. Employees in garish waistcoats are running over like it's a publican fire drill.
"Sure, I'd take McGregor in the fourth or Mayweather in the 10th," a visiting Dubliner, Conor McQuaid, says. "Mark my words."
In fairness, it's hard to mark your words when you won't mark them yourself. Which is it? You don't really think McGregor can do this, do you?
You have a terrible feeling he's about to get philosophical.
"He can't win," McQuaid says, eyes narrowing.
"That's why he can."
It's going on 3:30 now. Someone says to someone else that there's something going on at … you can't quite hear it, but they all rush off somewhere, dozens of them moving in a pack.
This week, McGregor encouraged the Irish to "run amok" in Las Vegas. He knows better. Irish sporting crowds don't do that.
They run amidst. They pour into a foreign city and take over one small corner of it – usually an awful chain pub called the Lazy Goat or the Frog and Fiddle or some such – and do not leave until they are forced to. They drink heavily; they spill into the road; they block traffic; they serenade the locals; they charm the press. By well-earned reputation, they are the gentlest mob in all the world of fandom.
These visiting Irish – as many as 5,000 of them – are here for the fight. But as with all Irish crowds, they don't expect much in the way of a result. They're here for a tipple and a singsong.
The Irish are so amenable, they prompted Mayweather to do something he never does – appeal to the other side.
"[Irish book maker] Paddy Power is paying out right now on my victory, and the fight hasn't even happened yet. Paddy Power believes in me. The Irish fans believe in me," Mayweather said in a video posted on social media. He was apparently delighted at the idea. It was one of the rare times a smile reached his eyes.
People do love a long shot. The odds on McGregor improved all week as dumb money poured in. By Friday, pragmatism was back in fashion. As of this writing, Mayweather is prohibitive 2-to-9 favourite (i.e. you have to bet nine dollars to make two).
If we're speaking the honest truth, the only person in this city who thinks Conor McGregor can beat Floyd Mayweather is McGregor himself.
He has variously predicted that he will win Saturday's fight by knockout in the first 10 seconds, the first round, the second or the fourth. He's made so many promises on that score, he seems to have lost track of them. Every time he does it, you can see the people around him struggling to keep their expressions non-commital.
Mayweather joked to a reporter that he would be arriving at the strip club he owns in town in good time on Saturday night because "it's only gonna last two rounds … That's what he said, right?"
When a man this thin-skinned is repeating your insults, it may be time to worry.
No one has ever knocked Mayweather out in a professional fight. No one's come close. Shane Mosley, one of the great lightweights in history, nailed Mayweather twice early in their 2010 fight. The first blow was so square that it hurt to watch. Mayweather rocked back a foot, gathered himself and over the next 10 rounds ground Mosley to powder.
McGregor is not Mosley. Not as a boxer. Not even close. That hasn't stopped him from talking like it, though, in his will-to-power way.
"What you see on TV is just an amplified version of Conor," one of McGregor's Dublin sparring partners, former women's mixed-martial-arts world champion Aisling Daly, told the BBC. "He has a genuine self-belief you can't teach. He believes himself to a point where eventually it manifests."
You cannot blame McGregor, 29, for trusting in acts of providence. His career is one of them. Four years ago, he was an apprentice plumber collecting government assistance. He came up hard in the toughish Crumlin neighbourhood of Dublin. Ten UFC fights later, he's the sport's biggest draw.
Combat is part of it, but his crossover appeal is largely down to his capacious ego, turned-up-to-11 bombast and peacocking style of presentation. In person, McGregor is somewhere between a corner boy and a barrister. The tailoring says, "Ask my advice," while the expression says, "What the [expletive] are you looking at?"
"There's two things I really like to do. Whoop ass and look good," McGregor said before one of his previous fights. "I'm doing one of them right now. On Saturday night, I'm doing the other."
I mean, come on. You'd watch a guy who talks like that, right? That's why we're all here. If only to see exactly how bad things can get.
"McGregor has no chance in this fight," Mayweather's last great foil, Manny Pacquiao, said. "In fact, it could be very boring."
Which sounds right.
Pacquiao also said he wouldn't be watching the match.
Which doesn't sound right.
Going over recaps of McGregor's previous matches in order is like watching a fish pull itself onto a beach, grow legs and walk off. That's how much he's improved. In MMA terms, he is an all-rounder. He does nothing remarkably well, but everything competently.
You can find boxing observers who will tell you that, despite the fact that he has never done this before, McGregor has a chance. They are the subscribers to the 'one lucky punch' theory of life. The Association of Ringside Physicians, a more fact-based organization, demurs.
"We were very surprised this bout was even sanctioned and was going to be permitted to carry on," ARP president Larry Lovelace told the New York Times. "The thing I really fear, truly fear is that somebody's going to get really hurt in this upcoming fight."
Lovelace is being a bit feline there. We all know which "somebody" he's talking about.
Part of this may be down to elitism. No boxing person wants to believe the sport can be mastered at the very highest level in two months – which is how long ago this fight was agreed upon.
But you do not need to be steeped in tactics to see McGregor's problem – he boxes like someone preparing to use his legs for kicking. In the all the footage he's released from camp, McGregor is too square and too primitive in his approach. He is open to attack at all times.
"I am boxing," McGregor said on the press tour that preceded his Las Vegas arrival.
Well, then I am skeet-shooting. Because I, too, have never done that before.
Where McGregor is relatively artless, Mayweather is Michelangelo. He poses himself at so severe an angle to his opponent that he becomes nearly two-dimensional in the ring. Long before he starts bobbing, Mayweather is a minuscule target. Then he moves, and becomes unhittable.
Canelo Alvarez – one of the best pound-for-pound fighters alive – spent 12 rounds missing so badly, it seemed as though Mayweather was teleporting around the ring. That was four years ago, but footage of Mayweather out of his camp suggests that speed is still there.
McGregor is not Alvarez, either. At this point, all we can know to a certainty about his boxing ability is that he owns a pair of gloves.
Long odds do not dampen the Irish spirit. Lost causes are a national inheritance. The visitors assumed control of Friday's weigh-in. Tickets were free if you had the foresight to get them, but they were still being scalped outside.
For the first time this week, there is an atmosphere of frenzy inside T-Mobile Arena. You can tell the Irish apart – they're louder, tipsier (even at 2 p.m.) and dangerously sunburnt. A half-dozen stretch out a tent-sized tricolour emblazoned with '49-1' – Mayweather's record if he loses.
"Remember, shoot footage, not people," a security guard tells people at the entrance. He's joking. You hope.
McGregor has the crowd by a large margin. He comes in dressed in hobo chic – flip glasses with the shades up, jogging pants and a flag as a cape. There is palpable tension on the stage as he is weighed, but he hits his mark with a half pound to spare.
He was 153.5 pounds on Friday. He'll be 170 by tomorrow night, by far the larger fighter.
Mayweather will give back 15 pounds or so – "Weight doesn't win fights. Fighting wins fights."
In an unusual (for him) stab at humour, Mayweather strips down to Paddy Power boxer-briefs and shamrock socks. McGregor stamps his feet like a bandy-legged leprechaun when he sees it. It's almost too perfect. It's almost as though they'd planned it this way.
McGregor screams in Mayweather's face through the final pose. It's hard to catch most of it, but you're certain it'd make a lip-reader blush.
"This is the worst shape I've ever seen him in," McGregor says, which is another unlikely thing. "I'm going to breeze through him."
You can see why the Irish are so taken with the guy. If you listen to him long enough, you start to believe his line of patter. It's said with such confidence. He's starting to make you believe people can will things into existence. The crowd roars his every word. The Mayweather fans on hand don't even bother to mount a sonic counter-offensive.
For Mayweather, it's a reminder that though he is the biggest fighter in the world, and the best, he is not loved. Even here, where he lives.
During his remarks, he is relentlessly booed. This isn't the tone he was looking for.
"The fans don't fight for you," Mayweather says. For the first time, there's a genuine edge in his voice.
He's not playacting this bit. This is real hurt showing. It's probably more than he's taken in the ring in a long while.
McGregor is strutting around the stage and the crowd has begun 'Ole'-ing him. This is his juice, right here. You can see him growing.
Nobody thinks he will win. Not even these people. But that's not the point. That's why the Irish always have the most fun. Winning is an occasional side-effect of a good time, not the goal.
"There's a saying," McGregor shrieks. "You'll never beat the Irish."
This gets the loudest cheer of the afternoon. Mayweather shakes his head. What is happening here? Are these people for real? Never beat them?
They do say that. But the unstated implication is "in the long run." McGregor doesn't have that kind of time. He spent years trying to make this thing happen.
Now he has about an hour to prove it was something more than a road trip and an expensive waste of time.
Cathal Kelly