Nadal beating Djokovic again at the USO ? That would close TTWThere are plenty of wacky unlikely possibilities out there (Zverev, Stan, Dimitrov, Med, etc).
But we all know there are only 2 (3 if you count Thiem) legitimate contenders, and the winner will likely have to play at least one of the other two. So the only realistic outcome that would genuinely surprise me is Nadal winning if he has to play Djokovic. That'd sure be something, and would silence a lot of critics (such as myself).