Looking at those gifs, I think that Mayweather is great at learning fighters tells and exploiting them.
Yes wel done you beat another fighter that you were supposed to. Now can you pick someone where your not an odds on favorite next time so we get value for money please!
Mayweather had Guerrero's timing, rhythm, habits down pat. That's the difference of Mayweather's skill level. He is constantly studying you reading you every move in the ring. Unless you have the ability to throw him off of readying you, you have no chance.
According to Guerrero, Mayweather felt his power early, and was "running" for the whole fight after that Sure busted up Robert's face pretty good for all that "running!" (plus, I thought his legs were gone? atsch)
At 147 or 154? Absolutely nobody. If he fought Sergio at 154 after Chavez Jr, I think it probably would have been pretty equal odds. With Sergio's last outing however, this would no longer be the case. Right now he'd have to go all the way to 160 to really be considered an "underdog" at all, which is impossible, considering he doesn't even make 154.