Who give's Mayweather the best run for his money?

[THE THIRD MAN]

Pacman is the only fighter out there that can beat Floyd, all the rest have no chance. Williams included.
For all the trash talking, for all the BS that sometimes comes out of Floyd's mouth, when it is all said and done he is a very smart fighter. He was in trouble in this fight with Mosley, one of the most dangerous fighters of the past 20 years, yet Mayweather worked out what to do within a round, he never lost a round after the 2nd and wins a fight that could easily have been just one more punch away from ending sensationally for him.
Pacman's different angles and speed both with foot and hand will cause Mayweather problems, (he will need to land bigtime very early) however do not underestimate the fact that Mayweather might just work Manny out inside a couple of rounds and frustrate the hell out of him and win a UD comfortably.
I see no one else out there with a chance against Mayweather. I hope this fight comes off by September/October!

[Spicoli]

Uncle Sam...little known contender out of DC with a mean streak and fights dirty.If he gets you hurt...he finishes you... ta dom tish