Despite back-to-back losses -- including a questionable decision defeat to Tim Bradley last year -- Pacquiao remains one of boxing's few remaining superstars. Possessing superior power, speed and accuracy, Pacquiao blazed a trail of dominance from 2008 to 2010, when he stopped Oscar De La Hoya, Ricky Hatton and Miguel Cotto. However, lackluster wins over Shane Mosley and Juan Manuel Marquez in '11 and an uninspired performance against Bradley in '12 have been signs that Pacquiao has begun to decline.
Last December, Pacquiao met Marquez in the fourth installment of a historic rivalry. It was a competitive fight early, with both Pacquiao and Marquez scoring knockdowns in the first five rounds. Then came the sixth, when Pacquiao, leading on all three judges scorecards, rushed into a picture-perfect Marquez right hand. The shot knocked him out, creating the first clear cut finish between the two fighters. Afterwards, on the advice of his trainer, Freddie Roach, Pacquiao took 11 months off, the longest layoff of his career.
Rios is not considered one of boxing's most skilled fighters, but he is one of its most entertaining. A come forward brawler carved from the mold of the late Arturo Gatti, Rios loves a good fight. He burst on the national scene in 2011, when he knocked out veteran Miguel Acosta for a 135-pound title. Rios moved up to 140-pounds in 2012 to stop Alvarado and claim a 140-pound title. He is not the most disciplined fighter; Rios has missed weight in two of his last four fights, costing him his lightweight title.
While Rios and Pacquiao have been respectful of each other, the tension between their camps has been palpable. Rios is trained by Robert Garcia, who was caught on film in 2010 laughing while two of his fighters, Rios and Antonio Margarito, mocked the symptoms of Roach's Parkinson's disease, and Alex Ariza, Pacquiao's former strength and conditioning coach who was fired by Roach in August. On Tuesday, a scuffle broke out between Roach and members of Rios's team at an open workout. During the expletive-laced melee, Ariza could be heard mocking Roach's problems with Parkinson's, including referring to Roach as a "stuttering prick."