If, after all is said and done, you turn into a lunatic when the team you were rooting for marginally misses the win, it won't work in your favor.
Refrain from screaming and pounding your chest like a gorilla. It's cute when a man cries, but not so cute when it's over a missed field goal. Reel in the crazy, or all of the things we mentioned (your wager, the chances of her asking about you, the possibility of seeing her again) will all fade away. We believe they call that a fumble.
Opt out of the over-the-top emotional response and the post-game sulking, and keep your eyes on the prize. Don't scare the shit out of the prize. Keep the whimpering and swearing to a minimum, and jokingly ask her to help nurse your wounds. Won't that temper your team's defeat?