Yeah, but you're forgetting two things:
1. His powers weren't weakened
2. He was being looked after by two other people with the same powers as him (Nolan and Oliver)
Superman, meanwhile, was pierced in the lung/heart by a massive spike by Doomsday (who was much more powerful than him, anyway), was weakened by exposure to kryptonite, and was surrounded by people much less powerful than him.