LAS VEGAS » Ask Shane Mosley how he can beat Manny Pacquiao, and the answer is match his speed and don’t be afraid to trade punches with a fighter who loves to trade punches. Ask trainer Naazim Richardson how his fighter can beat the best boxer in the world, and the answer is a little different.

"If he can be the best Sugar Shane Mosley there is, then Pacquiao has problems," Richardson said.

Unfortunately, Mosley hasn’t been his best for quite some time. And that could make for a rough time tonight when he tries to bounce back from a bad loss to Floyd Mayweather Jr. against a fighter who lately has been beating up everyone put in front of him.

The 39-year-old Mosley will try to resurrect his career with a signature win over Pacquiao, who once again is so confident of his chances that he has scheduled a post-fight concert on the Las Vegas Strip for all his loyal followers. Mosley must not only battle Pacquiao, who has won 13 straight fights, but the perception that he is a shot fighter after one last payday.

"It’s an opportunity to show people I’m not washed up," Mosley said. "You don’t lose your power. They say you lose your speed, but I haven’t lost my speed either."

Pacquiao certainly hasn’t lost his, and is coming off an 8-week training camp that trainer Freddie Roach said was his best ever. The Filipino sensation who travels with an entourage bigger than any Muhammad Ali had in his day, remains focused on boxing even while working a side job as a congressman back home and singing with his band.

His real work, though, comes in the ring in big pay-per-view fights. And ever since he sent Oscar De La Hoya into retirement by giving him a brutal beating, Pacquiao has been the most exciting fighter of his time.

"This is an important fight for me and millions of my fans," Pacquiao said. "You cannot underestimate him. He’s strong, throws a lot of punches and moves fast."

The Mosley of old certainly did that. But after losing a lopsided decision to Mayweather and struggling in a draw against Sergio Mora last September, many in boxing simply consider Mosley to be old.

Oddsmakers agree, making Pacquiao a 6-1 favorite in a fight that has been sold out for weeks at the MGM Grand hotel arena. The scheduled 12-round fight is for the WBO version of the welterweight title that Pacquiao won against Miguel Cotto.

Pacquiao weighed in at 145 pounds, while Mosley was at 147.

Pacquiao, returning to the same ring where he made his U.S. debut 10 years ago, is coming off two fights at Cowboys Stadium in Texas. In his last fight there in November he gave a bigger Antonio Margarito such a beating that Margarito was hospitalized and had to have surgery on his eye socket.

But Pacquiao (52-3-2, 38 knockouts) was also on the receiving end of a lot of punches by Margarito, largely because he’s the kind of fighter unafraid of mixing it up.

"When you like to exchange and you like to throw punches, you put yourself in harm’s way," Roach said. "That’s why Manny is the most exciting fighter in the world. I can’t take that away from him. He’s always liked to throw combinations, and when you let your hands go you leave yourself open."

Mosley, who gave up his ownership share in De La Hoya’s Golden Boy Productions to get the fight, is eager to find out just how hittable Pacquiao might be.

"I think it’s going to be an action fight from the beginning," Mosley (46-6-1, 39 KOs) said. "It’s going to get very interesting, very quick."

Pacquiao is expected to make at least $20 million, while Mosley is guaranteed $5 million plus a percentage of pay-per-view sales.