Floyd Mayweather, Jr. is the best welterweight in the world. In the opinion of most people he is the best pound-for-pound fighter in the world as well. What he is not is the most dangerous welterweight in the world. That title belongs to Miguel Cotto.

Some might assume on the face of it that being the best boxer in the world would, by definition, also make you the most dangerous fighter, at least in your weight class, if not on the entire planet. That would be a false assumption. Boxing superiority is one thing. Lurking, looming danger is quite another.

Mayweather is the kind of boxer who can sting you, embarrass you, even dominate you with speed, athleticism and creativity. He can, in some cases, hurt you too, as Ricky Hatton recently found out, but not in a lasting way.

Miguel Cotto breaks you down by breaking you up. He makes you pay a very high price for choosing to fight him, a price that leaves you not only beaten but with a bit of you left behind in the ring when you exit.

Thinking of the two of them one is reminded of the great junior welterweights Meldrick Taylor and Julio Cesar Chavez. Taylor was an innovative jazz artist, all flash and be-bop. He was athletic and brave with speed, fast hands and the originality of a virtuoso. Chavez, on the other hand, was a methodical, reliable wrecking ball. He was relentless, deeply skilled in his destructive ways and tireless. Pain did not affect him. Neither did flash. He simply wore you down with vise-like pressure and the kind of body shots that cause internal bleeding. He hit you until you wore out, as Taylor did, finally beaten so badly internally that he imploded and was never the same fighter again.

Mayweather may beat you in the way Taylor could beat you but Miguel Cotto beats you like Chavez did, in a way that leaves you a changed fighter and not for the better.

Perhaps just as critically, the danger lurks not only for Cotto’s opponent, who this Saturday in Atlantic City will be former “Contender’’ star Alfonso Gomez, but also for Cotto himself. Unlike Mayweather, we have seen Cotto bloodied. We have seen him on the floor. We have seen him wobbled and weary. We have seen his vulnerabilities. Yet we have never seen him vanquished.

There is, we sense, no adversity he is not ready to overcome, no problem he cannot cope with. Yet still we wonder in a way we will never wonder about Mayweather whether one night he will find himself in a dark place, facing a situation from which his heart and his skills cannot free him. We wonder how many times he can be in trouble and still end up leaving his opponent in a worse predicament.

Yet no matter what shape we find him in during a fight we understand Cotto remains always lethal in the same way Russell Crowe’s bloody Gladiator was always lethal except that Cotto is a real gladiator, not a cinematic one.

“Cotto is always dangerous,’’ said Hall of Fame trainer Emanuel Steward. “That’s why you won’t see Floyd fighting him.

“Floyd is the most talented welterweight in the world but Cotto is the most admirable. He’s a guy who always finds a way to win. We’ve never seen Floyd in the kind of adversity we’ve seen Cotto in and that’s not Floyd’s fault but what it tells you is that Cotto has a tremendous survival instinct.

“If things get too hot he can dance away and box. He can be a boxing machine if he has to be but if he has to be an aggressive fighting machine he can do that and that’s what he prefers.

“He can adjust to whatever he has to adjust to and find a way to win. Cotto fought the best guys at 140 pounds. He got knocked down. He was staggered. He was cut. But he found ways to win. He’s fought more of the top guys at 147 than anyone else with the same results. He wins.

“The guy endures. He beats you down. He is relentless in the way (Marvin) Hagler was relentless. And he damages you in the same way Hagler damaged people.’’

Floyd Mayweather, Jr. may indeed be the best welterweight in the world but how do we know? Since he first won the IBF title from Zab Judah and the WBC’s green strap from journeyman Carlos Baldomir, what welterweight has he beaten? None… because he hasn’t fought any.

Instead Mayweather has elected to fight a junior middleweight who is these days only an occasional fighter, Oscar De La Hoya, and a junior welterweight in Hatton. He fought for money, which is understandable, but while he was doing that the welterweights became Cotto’s province.

He beat the present reigning WBO champion Carlos Quintana to first claim the WBA title just over a year ago. Then he beat up Judah and Shane Mosley in back-to-back fights. He stopped Quintana and Judah and bruised Mosley’s face in a way we were not used to seeing. He did it with a vastly improved jab, withering and constant forward pressure, better defense than in his early days and a willingness to accept pain for the right to inflict it.

Of his 31 career victories, 25 have come by stoppage and nearly all those stoppages have been the product of the accumulated punishment Cotto inflicts, as was the case for the battered and bloody Judah in the 11th round of their encounter. Judah fought bravely for as long as he could and then finally collapsed, his will broken as much as his body.

Mayweather does not cause the kind of damage. He wins with deftness and style. He outboxes you and outfoxes you. Miguel Cotto mugs you. That is why, in all honesty, the most dangerous welterweight in the world may not be the best welterweight in the world.

Then again, as was the case with Chavez the night he broke down the stylish Taylor, maybe in the end he will be one and the same. Maybe, if Floyd Mayweather, Jr. really wants to find out, he’ll learn one night that the most dangerous welterweight and the best welterweight is the same guy and his name is Miguel Cotto.

“Miguel Cotto is a different brand of fighter,’’ said Gary Gittelsohn, Gomez’s manager. “He’s a different breed.’’

And a dangerous one.