This would be a battle. I wouldn't be surprised to see both guys hit the deck in this one. I think the difference is that hand speed of Pacquiao. Corrales(RIP) would be a very willing target and in his desire to go to war, he'd put himself in the line of fire and Pacquiao being much faster will land first and last. Diego is dangerous and could end it with a few big shots but I think Pac Man is the better man.
Manny via 10th round TKO.