Kaiba is so skilled that he practically got a whole film devoted to his hype in the Dark Dimension. It reminds me of just how awesome he is and it doesn’t hurt that Kaiba is one of the world’s greatest duelists. His overwhelming legion of monsters can strike down many foes and Fred Flintstone will have to be the victim this time. He has no way to defend himself and I believe Kaiba would win in a fist fight as well. He is simply too skilled in any arena of combat. Kaiba wins.