How do I beat the Chocobo Eater sidequest in Lightning Returns?

I'm on day 11 (with 2 days left) and I want to beat this guy! I've just beaten the Dead Dunes (finishing the main quests). This is only my second playthrough (mainly beating bosses with luck and a prayer) and I'm trying to do it with save data garb (Equilibrium, Guardian Corps and Knight of Etro) and I've got a little more than 7000 HP. I can't beat this guy! I know what the prize for doing so is and I want to beat him. Is there a way to beat him under these parameters? If not, what should I do? With only 2 days left, I'd rather not waste a lot of time on this, but it'll give me something to do before beating the game.