The former three division world champion,??who has fought both fighters, said he almost knocked down Mayweather in the second round of their 2010 fight.
And he believes the Flipino has to adopt an aggressive approach early on in Las Vegas on May 2nd.
???I almost knocked him out straight out the gate,??? Mosley told radio station On The Ropes.
???That would be a good tip for Pacquiao, he can???t give Mayweather a chance to get comfortable or to pick up on his rhythm.
???If he is going to win against Mayweather, it???s going to have to be in the first 3-4 rounds tops.???
But Mosley, nicknamed Sugar Shane, believes Mayweather???s defence is better which will give him the edge against Pacman.
He added: ???For the simple fact that I was seriously hurt with Pacman and was able to avoid him knocking me out and Mayweather is not hurt and is generally the best at avoiding punches, I would have to go with Mayweather.
???Plus Mayweather has [fitness coach Alex ] Ariza and Pacquiao doesn???t, so I am definitely going with Mayweather on this one, although I like Manny personally and wish him the best.???