Mayweather weighed in last fight at the most he has ever weighed(149), and Pacquaio after having gone down to 129 still weight 144 meaning they must be relatively close in weight... I think Pacquaio is would be more competition than Hatton form the aspect of his speed, and power, but that he might not have the chin. I think this would be a fight Mayweather would win, but a fight that would be fun to watch until Pacquaio would be stopped.