Will was stronger than he looked so no doubt the punch had been a surprise to him. The angel prepared himself, steeled his chest for the aftermath which would undoubtedly come from showing some assertiveness against the other man - there were always repurcussions for his actions. With his authority challenged this was expected.
Catching the other guy, Will toppled backwards then sideways, grappling with him. Arms, fists, legs, anywhere he could reach and make contact. Everytime he hit something, whether it was the dude or not, Will gave himself a point.