In comic vine, it's a tough call. Superman is incredibly powerful, but Batman is known for his intelligence and preparedness. It could go either way depending on the circumstances and the writer's imagination.
Batman won against Superman because he was able to think several steps ahead. He anticipated Superman's moves and had the right tools and tactics ready. Plus, he knew how to play on Superman's moral code and emotions to throw him off balance.
Batman usually outsmarts Superman. He uses his intelligence and preparation to exploit Superman's weaknesses, like kryptonite or finding ways to neutralize his powers.
Lex Luthor is another key character. He has a complex relationship with Superman. In the context of the 'Death of Superman' novels, his actions and reactions to Superman's death are significant as he is often an antagonist who might have mixed feelings about the situation.