But never was Mayweather as sharp, as precise and as good as he was on Saturday in a victory over Canelo Alvarez in their mega-fight before 16,746 at the MGM Grand Garden.
Mayweather has scored vintage victories over the likes of Diego Corrales, Jose Luis Castillo and Miguel Cotto, but never was he better than he was on Saturday.
Of course, C.J. Ross inexplicably called it a draw, turning in one of the most baffling scorecards ever in a major championship fight. She gave Alvarez four of the last five rounds.
Thankfully, judges Dave Moretti (116-112) and Craig Metcalfe (117-111) got it right, with Yahoo!-Eurosport concurring with Metcalfe. Yahoo! US gave every round to Mayweather, calling it 120-108.
Mayweather, though, wasn't ready to grade his performance. He raved about Alvarez and had kind words for Danny Garcia, who scored a decisive victory over Lucas Matthysse in the co-main event.
But he passed on judging himself.
"That's for everybody else to rate," he said. "Every time I go out there, I say I'm going to do something and I do it. I don't think it's bragging. I said I was going to win and I won. I fought 45 times and I won 45 times. But anything can happen in the sport of boxing."
Apparently not, though, in a Mayweather fight. He has a massive fan base, but hasn't been universally loved, in part because of his brash attitude and in part because he is, as he said afterward, "a thinking fighter."
Fans routinely love the blood-and-guts brawlers who are willing to walk through three and four punches just to land one of their own.
Mayweather is a stylist and uses speed, quickness, tremendous timing and great punching accuracy to win without being hit. He said he may have dislocated his elbow in the fifth or sixth round, but it was hardly noticeable.
Light heavyweight champion Bernard Hopkins said Mayweather's win "was a masterpiece," and raved about his complete game.
Alvarez said Mayweather's punches didn't hurt, but said Mayweather's elusivity was first-rate.
"He's very fast and accurate," said Alvarez, who had a mouse under his left eye when he showed up at the post-fight news conference after losing for the first time in 44 fights, dropping to 42-1-1.
The most impressive thing about Mayweather's performance Saturday was its totality: He dictated the way the bout was fought. He blistered Alvarez with a jab. But he also caught him with a series of hooks, crosses and uppercuts and just about any other punch a guy with gloves on his hands can throw.
The statistics bore out his dominance. Mayweather landed 232 of 505 punches, connecting on an insanely high 46 percent. He held Alvarez, one of the game's best offensive fighters, to 22 percent on just 117 of 526 punches.
The victory, the second in his six-fight, 30-month deal with Showtime, raised his record to 45-0 and might have been the one that guarantees he finishes his career with a perfect record.
There is no obvious, great challenger out there who seems to be able to beat him.
Promoter Richard Schaefer vaguely mentioned a move to 160 pounds, but Mayweather has never shown interest in going up that high. He weighed 150.5 pounds at Friday's weigh-in, but when he woke up Saturday, he was down to 146.
"I had the chef make me some good food," Mayweather said, beaming.
He weighed 150 when he walked to the ring, a half-pound less than at the weigh-in. That is almost never the case. Fighters always rehydrate the way Alvarez did. Alvarez was at the 152-pound contract limit Friday, but weighed 165 when he entered the ring.
So, it might not even be fair for Mayweather to meet a middleweight, though the only challenge at all for him in his final four bouts might be there.
He's likely to meet Danny Garcia, who also was brilliant in a unanimous decision victory over Lucas Matthysse Saturday in their bout for the WBA/WBC super lightweight belt.
Garcia blossomed into a star with his one-sided win, which he punctuated by knocking Matthysse down in the 11th. He didn't go so far as to call Mayweather out afterward though.
"I'm just a fighter," Garcia said. "I fight who they tell me."
He's planning to move to welterweight, and Mayweather's natural division now is welterweight, so that bout makes a lot of sense.
Garcia's father and trainer, Angel Garcia, is known for his over-the-top outspoken ways, but he kept it in check a bit when talking about Mayweather on Saturday.
"I would call it 'The Holy War,' " Angel Garcia said. "It would be a holy war, because there would be two gifted fighters in there."
As good as Garcia is – and he proved he deserves to be rated among the sport's elite after taking apart Matthysse – he'd be a massive underdog to Mayweather.
With Mayweather looking as good or better at 36 as he did at 26, there aren't a lot of fighters to choose from to match with him. He's lapped the field at this stage.
"I just took my time and took advantage of the opportunities that presented themselves," Mayweather said. "But I can't say this is my best. I still have four fights left."
But the countdown to 49-0 is on.
And it looks as if he's on an express route to perfection.