By Lem Satterfield

Nothing motivates five-time champion Shane Mosley like being the underdog.

Heading into a September, 2008, junior middleweight bout against former titlist Ricardo Mayorga, Mosley was coming off of failed bid to win the WBA welterweight crown in a November, 2007 loss to Miguel Cotto.

A Managua, Nicaragua, resident, Mayorga's past had included dethroning previously unbeaten WBA welterweight king, Andrew "Six Heads" Lewis, by fifth-round knockout, in March of 2002, unifying the belts with a January, 2003, third-round stoppage of previously unbeaten WBC king Vernon Forrest, and winning his return bout with Forrest by majority decision in July of 2003.

At 35-0 with 26 knockouts entering his first bout with Mayorga, Forrest had already scored consecutive decisions over the previously unbeaten Mosley after Mosley had twice defeated Oscar De La Hoya.

Mosley stopped Mayorga in the 12th round.

In January of 2009, Mosley was amid the worst period of his life against Mexican-born, then-WBA welterweight king Antonio Margarito.

Mosley's marriage to the mother of three of his four children was on the verge of ending in divorce, and, he was being scrutinized for allegedly knowing that he used designer steroids in connection with BALCO Founder, Victor Conte, before defeating Oscar De La Hoya in September 2003.

In addition, Mosley also was entering his first fight with Margarito under a new trainer, Naazim Richardson, after having fired his father, Jack Mosley.

But the largest crowd ever to witness an athletic event at the Staples Center in Los Angeles watched Mosley's ninth-round knockout victory over Margarito, who was stopped for first time in his career.

"They said Margarito was going to kill me. People said they were worried about my health. I had about three different things going on in my life," said Mosley. "But I just listened to myself. And I came out with the victory."

On May 7, at the MGM Grand Hotel in Las Vegas, the 39-year-old Mosley (46-6-1, 39 knockouts) will enter the ring as the underestimated opponent, yet again, against 32-year-old, eight-division titlist Manny Pacquiao (52-3-2, 38 KOs), who is after his 14th straight victory and his ninth knockout during that run.

Mosley is coming off of a unanimous decision loss and a draw, respectively, against 33-year-old six-time titlist Floyd Mayweather (41-0, 25 KOs), and, 30-year-old Sergio Mora (22-2-2, six KOs) in May and September of 2010.

"If it wasn't for those two fights, I don't think that I would be fighting a Manny Pacquiao. So as far as being able to fight Manny Pacquiao, I think that those two fights were needed," said Mosley.

"I don't think too much into it because I don't really care that people are saying whether I'll get knocked out or not. I don't care whether they say that I'm the underdog or not," said Mosley. "It's going to come down to what happens in the ring," said Mosley. "It is going to come down to what happens in the ring is when the referee raises the winner's hand. That's the only thing that matters."

Pacaquiao is coming off of November's unanimous decision over Margarito (38-7, 27 KOs) for the WBC's junior middleweight crown, one which Pacquiao has since relinquished.

"I look at Pacquiao's last fight, and Margarito landed the most punches ever on Manny Pacquiao. Margarito couldn't even land any punches on me," said Mosley. "So if Margarito can land that many punches on Manny Pacquiao, then I know that I'm fast enough to land a lot of punches on Manny Pacquiao."