David Diaz knows the reason he’s in Las Vegas this week and it’s not simply to beat Ramon Montano in a non-title fight. He’s there to impress enough pay-per-view customers when he opens HBO’s Saturday night card underneath the Manny Pacquiao-Juan Manuel Marquez rematch to convince them that a fight with Pacquiao later this year is something they will want to invest their money in.

Diaz, the 31-year-old WBC lightweight champion, fully understands this predicament he’s in. He has ears to hear and has been around boxing long enough to know why he has been put in the position of auditioning for a Pacquiao fight against this little known Las Vegan when he should be defending his world title for a far bigger payday. He knows there is an inherent unfairness to this but he also knows enough not to concern himself with it or with anyone or anything else but Ramon Montano this week.

“People, they can say what they want but for me it’s a big fight,’’ Diaz (31-1-1, 17 KO) said just before he left Chicago for Las Vegas. “I’m not as well known as some guys so every fight I have to look my best.

“To be in a (non-title) fight like this when you’re a world champion is a little disconcerting. It gets to me a little bit but I’m a patient guy. I know I have to take care of who’s in front of me or I’ll be back stuck on the outside.’’

That’s where the 1996 Olympian seemed trapped until he stunned Jose Armando Santa Cruz on Aug. 12, 2006, coming back from what had been a hard night to stop him in the 10th round and lay claim to the WBC’s interim title. That interim period ended unexpectedly the following February after Joel Casamayor failed to make weight against Diego Corrales and was stripped of the not-so-interim version of the WBC title he held and Diaz was named full champion.

One would think that would open some doors for him but it took six more months before he got his first title defense. And  when it came 51 weeks after first stopping Santa Cruz it was worth the wait. On that night Diaz not only lived his dream of being introduced as a world champion in his hometown but he also beat back the challenge of future Hall of Famer and Mexican legend Erik Morales, retiring the former champion for all intents and purposes by beating him to the punch time after time on his way to a unanimous decision.

Yet even then he was forced to wait, having to settle for this non-title 10-rounder against Montano (14-3-2, 0 KO) with the promise that if he wins he’ll be in line for a big payday against Pacquiao, who intends to move up to 135 after settling things with Marquez four years after they fought to a stunning draw in a fight in which Pacquiao dropped him three times in the opening round only to watch in horror as the gritty Mexican battled all the way back to the brink of victory.

Now Pacquiao and his promoter, Bob Arum, have Diaz in their sights. All he has to do is fight well enough on HBO to make the match salable to the larger public. Diaz understands that this is what this is all about but knows he has to ignore it to insure it happens. More importantly, he has to never forget the basic lesson of prize fighting.

“Nothing is a sure thing in boxing,’’ Diaz said speaking from hard won experience. “I know that. So my ONLY concern is Montano. After I step out of the ring Saturday night then I can think about the next fight.’’

That is easier said than done however, even for a guy who has walked a hard road since first turning professional after the Atlanta Olympics. After going 175-16 as an amateur and winning three national Golden Gloves titles, Diaz lost in his second Olympic match to Oktay Urkal, who has unsuccessfully challenged three times for the light welterweight title and once for the welterweight championship. From there he would begin a long, slow route to his own world title, much of which he now admits was due to mistakes in judgment he regrets.

But regardless of how long it took him, David Diaz has lived his dream. His hand was raised in a world championship fight, one time against one of the finest fighters Mexico has ever produced. Yet even after that victory over Morales six months ago there were critics who insisted he’d beaten a shell of what Morales once had been. Diaz heard those stories just as he’s heard the ones that he’s one victory away from facing Manny Pacquiao. He’s heard them but he hasn’t listened to them.

“It really doesn’t bother me what people say,’’ Diaz insisted. “Everybody takes it so seriously but I just laugh. The next guy I beat will have had a cold or an operation on his appendix. It really doesn’t bother me what people say. Beating Morales was something I’ll never forget.

“It happened in my hometown. The guy thought he’d done everything and I’d be a cakewalk. He had no respect for me. But I showed up to fight. He left thinking more of me than he did going in.

“I was so calm in the locker room. It was like, ‘Wow. Are you OK?’ I was so well prepared I felt I was stronger and I felt I’d win. I wasn’t jumpy before the fight and I wasn’t surprised after the fight.’’

Now Diaz is facing a far less formidable opponent yet one just as dangerous to his future because there is no margin for error if you are a guy like Diaz. Fighters like him, even when they have a world championship belt around their waist, are considered by many to be accidental champions who came along at the right time and in the right place.

A week ago another such man, 36-year-old Nate Campbell, laid claim to the WBA, WBO and IBF versions of the lightweight title Diaz holds by upsetting another Diaz, Juan, by majority decision. His WBC counterpart watched with some surprise as Campbell out hustled Diaz to himself become an unlikely champion and he was reminded not only of his own story but also about why guys like Ramon Montano, guys few people have ever heard of, are dangerous even if the world believes they are not.

“I was surprised,’’ Diaz admitted. “Nate just took his heart out. Nate didn’t step back one step. I felt good for him. We were guys left on the outside looking in but I got my shot and won and he got his shot and took advantage of it. That’s what this sport is about. On any day you can become a world champion.

“To be honest, I still don’t think much about the championship really. I put the belt away in the closet. I don’t look at it. I concentrate on being hungry. I’m still the same guy I was before. I know Montano is coming in thinking this is his chance to make a name. I don’t think less of this guy.

“He throws in volume, like me. He’s tough. When I first heard about this fight I was wondering why I wasn’t fighting one of the other champions but Casamayor and Diaz were booked so we took this fight. I’m not a picky guy. Honest to goodness. I’ll fight whoever they put in front of me. What’s important isn’t remembering you’re a champion. What’s important is remembering you’re a fighter.’’

If things go well for the fighter who is also a champion on Saturday night, the widely-held belief around boxing is the next person they’ll put in front of him will be Pacquiao, who is among the top three pound-for-pound fighters in the world. That night, if it comes, will not be like Saturday night. That night David Diaz will again be the underdog, just like he’s been throughout most of his career.

He’s not insulted by that just as he’s not insulted by the idea that a guy like Montano will come to the Mandalay Bay Events Center believing he can do to David Diaz what Diaz did to the unsuspecting Santa Cruz and the arrogant Morales.

“I welcome guys that think they can beat me,’’ Diaz said. “I know everyone is shooting for me now. I really don’t care what other fighters think of me. When I beat them it’s a shock to them but not to me.’’

*thanks for Team Diaz for the photo