Moria's battle WAS from the inside of Oz. Once Oz was defeated, there was only Shadow Asgard and the knockout punch. At this point Moria had already sustained heavy damage from nightmare Luffy's assault on Oz.
I am not saying Moria deserved to win that battle. He had it coming for being an idiot and underestimating Luffy. I just don't think it was the same as the single handed ass whooping Luffy delivered to Lucci, Enel (Ok in this case, Luffy had the advantage on a technicality, but he still handled the situation on his own) and Crocodile.