LAS VEGAS – Inexplicably, to him at least, in a town built on odds, the numbers are against Joel Casamayor this week.

He finds this baffling.

Holder of nothing more than a magazine’s belt, the linear lightweight champion has spent the last 12 weeks preparing for what apparently men who make odds for a living believe he cannot do. He has been preparing to defeat one of the best pound-for-pound fighters in the world, Juan Manuel Marquez. He sees no reason why anyone would assume he will not do this despite the fact Marquez is a three-time world champion in two weight classes and considered by most observers to be among the top five pound-for-pound fighters in the world because, after all, hasn’t he almost always won such fights?

Dating back to the 1992 Olympics, when he won a gold medal for Cuba at the Barcelona Games, Joel Casamayor has been a fighter who rises to the occasion and that is what this fight is to him – an occasion.

The 37-year-old Cuban recognizes Marquez’s vast technical skills but after he considers them, he then considers himself. It is then that the 3-1 odds against him become laughable in his mind. Maybe that’s how you think when you’re the kind of guy who believes you can defect from a Communist country in broad daylight and get away with it. You think about yourself, not what the other guy can do.

“I’m an all-time fighter,’’ Casamayor said. “I stand up in big fights. Sometimes I’m not a (good) under card fighter. I know when I lose my vision I lose it hard but I haven’t lost it at all. I’m a great fighter and great fighters stand up in big fights. That’s what I needed and I got it.’’

What Casamayor is referring to are his last two fights, a highly disputed decision over Jose Santa Cruz last year after a 13-month layoff that was awarded to Casamayor but was so controversial the New York State Athletic Commission questioned each one of its judges about what they were thinking. That was quickly followed four months later with a 10th round stoppage of Michael Katsidis in which Casamayor dropped the raw as an onion Australian twice in the first round before being knocked out of the ring himself in the sixth. He came back and finish Katsidis off with a perfectly thrown counter left hook the young and wild Australian slugger ran into at a time when some felt he was putting increasing pressure on a fading magazine title holder.

What caused the latter fight to raise questions about Casamayor’s future is that former lightweight champion Juan Diaz just picked Katsidis apart two weeks ago, beating him up, down and sideways all night long. That Casamayor had his struggles with him, coming on top of his lackluster performance against Santa Cruz, has left many in boxing wondering if the end is now in sight for an aging fighter who has been in three wars with Diego Corrales, one with Acelino Freitas, another with Jose Luis Castillo and who, frankly may be 37 or may be an El Duque 37 – which as the Yankees found out about Cuban pitcher Orlando Hernandez is an age calculated more in dog years than human years.

Regardless, Casamayor has always been cocky to the edge of arrogance and with proven reasons inside the ring, so when such doubts are presented to him he bristles. He understands and accepts the skill of Marquez, who is coming off a split decision loss to Manny Pacquiao that did little to lessen the esteem in which he is held because many felt he’d done enough to win after drawing with Pacquiao four years ago in an equally tight contest. What he wonders is if people have forgotten who he has always been in these kinds of situations.

“Everyone is going to see on Sept. 13 that we got a surprise for him,’’ Casamayor (36-3-1, 22 KO) said. “You are going to see the best Casamayor you’ve ever seen.

“There is nothing to worry about. The only thing you got to do is just do your business in the ring. At this stage of my career the only thing I got to do is just get into the ring and mind my own business. You have to fight, that’s it.

“Basically I’m going to do what I always do – break people down technically. I’m super prepared, not only physically but mentally. I’m a savvy guy in the ring. I’m not a guy that’s out there like a robot or nothing like that. I’m a guy that gets loose in the ring.

“When I get in there, I invent. I’m the guy that dictates the pace. I’m very happy to fight Juan Manuel Marquez. I want big fights and this is a big fight. I’m going to show everybody who I am. I’m not interested in that kind of Santa Cruz stuff. Everyone knows what happened. I hadn’t fought in a year. I want the biggest fights possible and that is Marquez right now. I don’t think there’s any discussion of who the best lightweight in the world is. I’m recognized as the lightweight champion of the world and the winner of this fight is going to be the best lightweight in the world and, in my eyes, will be one of the best pound-for-pound fighters in the world.’’

Later in the day, during a brief hallway encounter at the MGM Grand, a laughing Casamayor held up five fingers when asked how he really thought this fight would end.

“Five rounds!’’ he said. That may seem unlikely even though this will be the 34-year-old Marquez’s first fight at 135 pounds after having spend his career fighting at between 122 and 130 pounds because he has never been stopped. He has, however been down numerous times, including four times in his two fights with Pacquiao and once against Marco Antonio Barrera and those knockdowns, and his own unwavering faith in himself, have Casamayor believing at some point Marquez will abandon the counter punching style he favors and attack. When he does, he will have him where he most likes to have an opponent because he, too, would rather counter than lead.

“I was a little rusty in the Santa Cruz fight and there are no excuses for that,’’ Casamayor said. “My mentality is different in this camp when you know you’re in a big fight and you need to win to get to the next level.

“Juan is a great fighter and everyone knows I’m a great fighter. He’s smart in the ring just like me. It’s going to be a great challenge. What other fight is better for me?

“I heard all the whispers coming from the outside but as a fighter you know what you got inside. Your heart doesn’t lie. I’m going to show everybody I’m still the best at 37 years old. I’m looking at this as if I have no next opponent. I only got one and that’s Marquez. If I don’t get Marquez there is no next fight.

“I can’t guarantee a knockout. A knockout comes by itself, like when a baseball player hits a home run. He’s not hitting for the home run he’s just swinging for a nice hit and then he ends up hitting it out of the park. But come Sept. 13, I can say one thing – someone is going to get hit out of the park.’’

Considering the smile he’s been wearing all week, Joel Casamayor believes he’ll be the one with the bat in his hand when the moment is right Saturday night.