One Piece Episode 446

[Splash!]

How is that? A brutally battered Luffy still managed to beat Moria's Shadow Asgard with relative ease

My personal opinion is that Moria screwed up with the Shadow Asgard. He let the emotions get the better of him and sucked in too many shadows.

Edit: Also the Moria battle involved teamwork from the strawhats, in contrast to the Lucci and Enel battles. It doesn't count for Luffy as beating someone 'on his own'.