Barry N. Malzberg 
Tactics of Conquest 

"You mean we’re truly going to play for the fate of the Universe?""Exactly, " the Overlord said, "a forty-one game chess match to be broadcast throughout all civilized sectors of your Universe so that everyone can witness it.""But why chess? Why me? Why this planet?""Because chess is ideal for such a final judgement; it is a methodical game with absolutely no element of luck, and therefore there can be no complaints by the loser. Chess is known only to your plant, and you and your opponent are the most evenly matched living players. Good against evil. No other chess players are so close in true potential abilities. There is no other reason."