The context makes it clear he's saying that it's a "thowaway" only in the sense that he doesn't think it should interrupt Phoenix's momentum from Game 4. I.e., now that it's over, throw that game out, because it wasn't representative. He uses this idea a lot when something extraordinary happens, like the team shooting 30% for no apparent reason, or whatever. He means that you shouldn't draw hasty conclusions from the game. His comments before the game were crystal clear that he thought the Suns could win and would go all out to try to win, so it wasn't a "throwaway" in the sense that he was throwing in the towel before the game was played.