Power dampening wont cancel out her regen, physics, strength, or reality shift, but it'll cancel everything else out and slow down those effects at least. So yeah, at least you wont be fighting her full power when the fight does come XD.

Though to be fair, you could probably delay that fight for awhile. xD

You should try going deus ex on her head, IE, talk her down or confuse her, You'd probably get away with it. That was a good game.