Superman could kill Batman from orbit, or fly at him so fast that he’s invisible, and probably just the shockwave itself would kill Batman.
Batman’s smarter than Superman, and would probably figure out what’s coming and prevent it from taking place. Again, he has Kryponite secretly stored just in case he would ever have to use it...if he struck first, Superman would be rendered powerless and wouldn’t be able to do anything.
It’s not just me; it’s happened in the comics before (The Dark Knight Returns)...Bruce is the one man who could ever beat Clark Kent.