the reason that Teach definitely beat Ace has nothing to do with how big the attacks are, or anything of that nature. We all know that Teach wins because it is important for the story for this to be the case. Note that at this point in the story, Teach is Luffy's most natural arch nemesis. I'm not sure if Ace will survive or not. That isn't important. More important is that Teach needs to progress with his plan and continue to succeed so that he maintains a status of being worthy to fight (and obviously lose to) the Straw Hats.