Right - it really depends on what he was referring to.
To himself: Damn, I'm good!
To gioeyo: Damn, you're good!
To the game: Damn, this is a great game.
To a particular play/hand: Damn, that was a nice hand! / Damn, nice play!
It really all depends. For example, if it was a close game, it could mean, Damn that was a close game! (close in a positive sense, meaning challenging but fun). Or maybe he meant, I won the game, but damn you're good!