Note that we're focusing on the spectacle here, and not claiming that it will be one of the great competitions of all-time at T-Mobile Arena.
On paper, the 12-round, 154-pound fight is an abject mismatch.
Mayweather, of Las Vegas, was a boxing champion in five weight classes, is 49-0, tied with legendary heavyweight champion Rocky Marciano's undefeated record.
McGregor, of Dublin, Ireland, was the only fighter to ever simultaneously hold two UFC weight-class titles (featherweight and lightweight, the latter of which he still holds).
McGregor has never competed as a professional boxer. Under boxing rules, he seems to have as much of a chance of winning the bout as the famed All Blacks rugby squad would have playing the New England Patriots under NFL rules.
But it's the spectacle, the sheer hype and drama and the magnetic force of the personalities involved, which is going to make this a must-watch event. It is the promise of the two biggest stars of America's two favorite combat sports colliding.
There has been no comparable combat sports event since the 1976 mixed-rules bout between then-heavyweight boxing champion Muhammad Ali and Japanese professional wrestler Antonio Inoki, which went to a 15-round draw in Tokyo. But that bout was a near-flop at the gate, rescued from financial catastrophe by a hot accompanying closed-circuit wrestling broadcast along the East Coast.
By contrast, the gate at T-Mobile Arena for Saturday's event has surpassed $100 million and the pay-per-view buys, at $99.95 a pop, are expected to make a run at topping the industry record of 4.6 million set by the 2015 Mayweather-Manny Pacquiao bout.
Mayweather, who doubles as the fight's main promoter, is expected to take home upwards of $300 million. McGregor is expected to make $100 million, by far the biggest one-night haul for an MMA fighter.
The bout was hyped last month in a raucous, three-country press tour. Accusations of racism against McGregor and homophobia against Mayweather due to comments each made drew the ire of social commentators who don't usually pay attention to fight sports, which only helped amplify the spotlight and bring yet more attention.
Since then, most of the hype has been angled at putting forth the notion McGregor has a chance. At Mayweather's suggestion, the Nevada Athletic Commission signed off on allowing the fighters to wear eight-ounce gloves, as opposed to the standard 10-ounce gloves for their weight class. It is an attempt to convince the public that McGregor has a better chance to pull off the one-punch knockout.
And McGregor's promoter, UFC president Dana White, leaked footage of the Irishman dropping former world boxing champion Paulie Malignaggi in sparring, footage the latter claims was selectively edited, to hype McGregor's boxing skills.
At a Wednesday press conference in Las Vegas, Mayweather continued hammering the notion that McGregor could be a dangerous foe.
"Conor McGregor still has a hell of a career," Mayweather said. "He's a hell of a fighter, a hell of a fighter, he's a standup guy, he's a tough competitor, it's not going to be an easy fight. It's going to be blood, sweat, and tears."
That pitch has worked, too: A reported 95 percent of the money wagered in Las Vegas has come in on McGregor, making him a closer-then-it-should-be, plus-300 underdog as of Wednesday. It would leave the city's sportsbooks vulnerable to an epic bloodbath should McGregor pull off the upset.
If you're looking for a reason to convince yourself that McGregor could win, here's the blueprint: McGregor is 28 to Mayweather's 40. Mayweather hasn't fought since September 2015. McGregor is larger than Mayweather, having fought as high as 170 pounds in recent years, while Mayweather spent the bulk of his prime at 147. If McGregor exploits the grey areas in the rulebooks and wears him down in the clinch, he could catch a rusty Mayweather with a wicked left hand.
For his part, McGregor says what he's been through in MMA is tougher than anything a boxer can throw at him.
"Have you ever had a shin bone bounce off your cheek bone?" McGregor asked Wednesday. "You ever come through that? You know what I mean? That's the game I come from. So, they can say what they want, I've come through a lot tougher than any of these have come through. We are prepared."
But then reality settles in.
Mayweather has never come close to losing a fight and might be the greatest defensive boxer in the sport's rich history. His combination of speed and footwork, against a fighter who can't use most of his MMA weapons, likely will make for a typical Mayweather fight once the bells rings.