Batman shouldn't stand a chance.
Bruce Wayne, for all his training, for all his discipline and for all his gadgets, should not be able to stand up to Superman. It shouldn't be possible, there's just no way. If these characters were real and if The Man of Steel's hand was forced, then he could crush The Dark Knight's windpipe with one subtle squeeze of his thumb.
With one very small, very quick blast of heat vision, he could incinerate Batman and reduce him to ashes. He could blow one single shot of his icy breath in Batman's direction and freeze him solid, crystalizing his insides and killing him instantly.
With one punch at a quarter of his strength, Superman would demolish Batman's face, rendering it unrecognizable and liquify his brain from the impact. This would not be a fight, it would be a massacre and there is absolutely no way Batman would ever be able to survive.
That's what the everyday person would say. For non comic book fans, this one is not even close. But fanboys know better.
The last son of Krypton may be a god among men, he may be the most powerful being on the planet and he may have powers far beyond any human ability or comprehension. Superman can do practically anything and can outlive everyone on this planet by centuries; all of that is true.
But Batman can take his lunch money from him and send him crying home to his momma any day of the week. That much is also true.
Why is that exactly? Why do fans believe Superman would go down like Ronda Rousey to Holly Holm? Batman doesn't have any powers, he has no magic, he has nothing other than his mettle and his tech. How does that give him an advantage over his opponent?
The truth is Batman's advantage is with the man himself; he will do whatever it takes, short of murder, to win the fight and Superman will not. Superman will punch, he will hurl, he will lift and he will throw but will he give a low blow? Will he poke the eyes? Will he hit from behind?
Will Superman heel out like a pro wrestler?
The answer is no. There's a reason why John Cena is described as WWE's Superman. John would never do any of those things in a fight, he will always look his opponent in the eye and fight on his own terms. He would never stoop to the level of the guy trying to hurt him.
Superman is super because he holds himself to a higher standard. He sets the example. Kids and adults of all ages can look up to him because he always does the right thing. He fights for truth, justice and the American way and those same principles would apply even against Batman.
The Man of Tomorrow would be hopeful that he could reach Bruce. If Batman goes off the reservation, Superman would surely believe he could bring him back. He knows down deep that the Caped Crusader is a good man that strives to do good for his city.
Superman knows that Batman is only human, capable of making mistakes and also worthy of redemption. Superman would fight fair, he would fight with compassion and he would do those things while Batman is rolling over him with a Kryptonite tank.
This is why fans believe Batman would not only be able to hold his own but that he would win; Superman just would not do what the situation called for and Batman would.
He's trained in the martial arts; his body has withstood tremendous amounts of punishment, he's been tortured, stabbed, shot, beaten and suffered a broken back. Physically he can take a beating and get back up for more. Mentally he can outsmart, outthink and be ready to outmaneuver his opponent before his opponent makes the first move.
He studies his enemies and knows them better than they know themselves. His mind can go places that Superman's can't because he's willing to open a door that cannot be closed. Batman has seen the evil that men do, he understands it and he has conquered it.
Batman is the night and the night swallows the light. Superman can't accept that he doesn't believe that. Therein lays Batman's advantage.
So the fight that seems like a slam dunk on paper is really not; Superman is not so god-like after all and Batman is not so insignificant. This one is much closer than the average person could ever realize and the outcome is far less predictable than that same average person would ever guess.
This is why Batman will always have the upper hand and why he will almost always win. Turns out he stands a pretty good chance after all.