For all that Floyd Mayweather says it's not in his make-up to lose, there's one fight he just can't seem to win.

Mayweather burnished his perfect ring record and reputation as a consummate craftsman with a 12-round unanimous decision over Manny Pacquiao on Saturday only to depart the MGM Grand Garden Arena to a chorus of jeers.

It was an unequivocal victory that stamped the 48-0 American the best of his era.

But in the crowning moment of his career, the 38-year-old champion was defiant in the face of the evidence that his undeniable skills haven't earned him a place in the hearts of boxing fans of greats like Muhammad Ali, Sugar Ray Robinson and Sugar Ray Leonard.

Mayweather professes not to care.

"A 19-year career with no punishment on the body -- and the money," he says of what he considers the defining characteristics of his greatness.

Those hallmarks, however, diminish him in the eyes of some.

Mayweather's impressive resume lacks the kind of wars that make the greatest ring theater: Ali versus Joe Frazier, Marvin Hagler versus Thomas Hearns.

Although he's ridden his perfect record to a reign as the highest-paid sportsman in the world, his insistence that the money is the goal makes him hard to root for.

Making it even harder is a string of incidents of violence against women -- including a two-month jail stint for assaulting the mother of three of his children.

Perhaps it's no wonder Mayweather sounded tired of it all.

"At one particular time, I loved the sport of boxing," he said. "I wanted to go to every fight. But I've just lost the love of the sport.

"My love and my passion for boxing is not the same, like it once was, but this is my job, to go out there and be at my best when doing my job."

Mayweather insists that breaking Rocky Marciano's 49-0 record is not a goal for him.

He says he'll retire after one more fight in September -- and it may not even be for a championship if he follows through with a plan to relinquish all of his title belts.

READ ALSO: Mayweather vows to retire after September bout

Who the opponent will be -- and whether Pacquiao might get a re-match -- wasn't a topic he cared to entertain immediately after the fight.

READ ALSO: Money trumps Pacman

"It hasn't even been even two hours," he said.

But he didn't mind looking ahead even further -- to the time when the sport he took up as a toddler is behind him.

“I don’t think I’ll miss the sport of boxing,” said Mayweather, who will no doubt remain involved thanks to his Mayweather Promotions company and the young fighters who train at his Las Vegas gym.

"I don’t watch boxing any more, unless it’s someone coming to my gym," he said. "I don’t watch boxing like that.”

PHOTOS: Fight of the century : Floyd Mayweather vs Manny Pacquiao