Final Fantasy X - Boss: Crawler?

I've been trying to beat this thing for days, it pretty much ruins the fun of the game because it's so hard. Maybe I'm just being an idiot but I just CANNOT beat it. I looked up some advice and maybe it will help when I try again, but does anyone have anything they found worked well for them? THe mana beam pretty much kills everyone but Auron and I have to use all my stupid potions to regain my health. Enough rambling for now, so I'm basically just asking if anyone has any tactics on beating the Crawler.