What Mosley believes boxing fans don’t understand is he’s got a real shot to pull off an upset over the best boxer in the world.

"It’s going to get very interesting, very quick," Mosley said.

Oddsmakers in this gambling town don’t agree, making Pacquiao a 6-1 favorite to beat Mosley when they meet Saturday night at the MGM Grand Hotel. But Pacquiao himself says Mosley may prove to be his most difficult fight since he became a superstar by beating Oscar De La Hoya.

"He’s not an easy opponent," Pacquiao said at Wednesday’s final pre-fight press conference. "He’s the kind of fighter you can’t underestimate."

Pacquiao said he has not done that, training eight hard weeks to get into the kind of shape his adoring public has come to expect. He’s expecting the Mosley of his prime, not the fighter who looked very ordinary in a loss to Floyd Mayweather Jr. last year, followed by a draw with Sergio Mora.

"He moves like he’s 31, 32 years old," Pacquiao said. "He has hand speed, and he has foot speed."

Many in boxing think otherwise. They see the 39-year-old Mosley as a shell of the fighter who beat De La Hoya twice and has held titles in three different weight classes.

Mosley rocked Mayweather early only to fade as the rounds went on. He looked old and tired against Mora.

But styles do make fights, and Mosley believes he has the speed and punching power to trade punches with a fighter who likes nothing better than a good brawl in the ring.

That could make for an interesting fight — even if it’s not the fight against Mayweather most boxing fans want to see.

"It’s an opportunity to show people I’m not washed up," Mosley said. "My legs are good, they’re strong and ready to go. You don’t lose your power. They say you lose your speed, but I haven’t lost my speed either."

Mosley will earn a minimum $5 million to take on Pacquiao, the boxer-congressman-singer who has become a worldwide phenomenon. He may earn every penny of it if Pacquiao looks like he did in dismantling Antonio Margarito in his last fight in November.

The only knock on Pacquiao — who is guaranteed $20 million — is that he spends too much time doing things that have nothing to do with boxing. That includes an Oval Office meeting with President Barack Obama when Pacquiao was in the United States in February to begin promoting the Mosley fight.

But he’s proven he can manage them well, whether it’s his duties as a congressman or recording his latest music CD.

Pacquiao combined some of those duties at the press conference, with an announcement that he will wear yellow gloves in the ring as a message of hope in fighting hunger in his native Philippines. He also called out songwriter Dan Hill in the audience, whom he teamed up with to recently record and release Hill’s song "Sometimes When We Touch."

But boxing is his main job, and Pacquiao gave every indication he plans to put on a show in an arena that has been sold out for five weeks. It’s the same arena where he made his U.S. debut 10 years ago as an undercard fighter who took a bout on two weeks’ notice and still won.

"It’s nice to be back here," said Pacquiao, whose last two fights were at Cowboys Stadium in Dallas. "This is an important fight for me and millions of my fans."