That was mostly because he was overconfident and got beat by his own pride.Originally Posted by The Archangel
Moria was pissed that Luffy beat him by using his own power so his pride got the best of him. He absorbed way too many shadows and made it hard for him to have full control over his body, on top of that he already took a lot of damages from Nightmare Luffy so that didn't help. I'm pretty sure Moria would've won if he only absorb like 200-300 shadows while retaining full control.