knew that Pacquiao needed to come at him to take the fight from him. All Mayweather had to do was make sure he didn't get hit or hurt, and get in enough punches if his own to win the rounds. Of course he wasn't going to let himself get into a position where Manny could do some damage.
If you don't have to get your head knocked off to win the fight, why put yourself in a position where it could?