When you see a doctor?
As long as you have a decent timeline, you'll be okay claims-wise. Document. Remember the day of the Game, where you were, what happened. Then, if by Tuesday, you're still in massive pain, hit the MD. If the injury cause is the match, or falling off the barstool, your Accident Medical Cover will kick in.
Oh, and don't do that yourself. Let me do it for you.