(Part one of Art and Sports can be found here)
I think both art and sport are at their most transcendent when order breaks down (by accident or by design) and improvisation takes over.
With a lot of sports, this is a built-in feature: you make a move, your opponent responds with his own move, and, based on this new configuration, you make your next move, ad infinitum, creating a feedback loop. In chess, the period of the loop can stretch out as players (or supercomputers) run through possible permutations and outcomes. In football, it may be only a fraction of a second as a quarterback reacts to a blitz.
The array of choices available for any given iteration of the feedback loop isn’t infinite. In sports, it’s bounded by the rules of the game; in music, by the key and time signature. Staying in bounds keeps things intelligible, but transcending the bounds makes art.