Is Sergio Martinez A Serious Threat To Manny Pacquiao?

I wouldn't consider him a threat, Sergio is the middleweight champion of the world, an extremely talented guy, but it's a different division. If he starts talking seriously about moving down in weight then he becomes a threat because I seriously doubt Pacquaio would consider moving up more, it's just not physically possible. Any boxer in the world is going to want to fight Pacquaio, same with Mayweather because they are living legends, the reward of beating them is instant fame and fortune.