You do realize that to defeat this type of being, you need some magic to create a force field in order to repel her attacks. If not, then you'll have to move very quickly to avoid the flames. Telekinesis helps in dousing the flames with nearby water sources, but I'm guessing you don't have that. You can't allow hesitation either. If you get in close, rip out her heart as soon as possible.
At any rate, since that was last night I assume you either already showed up to the club, or not. Tell me you didn't disappoint our entire kind by not fighting her to at least a draw. You don't have to kill her, but anything less than a draw after accepting such a challenge is disgraceful. If you backed out...then you're a smart man, relatively speaking.