Spider-Man has lost plenty of battles, sometimes against low-level villains. But before you know it, he's back on his feet beating the crap out of some überpowerful alien cosmic dude.
That's why I like him, he can be godlike when he fights, but also a bit clumsy and stupid. You never know what you're going to get 😉.
But against Batman... I'm well aware that if the two should ever fight each other, the writers will have to come up with a solution for the fact Spider-Man has no weaknesses Batman can use against him AND is Batman's superior in every physical aspect.
But Batman is too popular to get his ass handed to him by Spider-Man, so they will probably come up with something retarded as "I've studied all your moves, Spider-Man, that's why I beat you" or "When I first saw you, I immediately knew you possess a spider-sense, so I created a formula to kill off this sense, and that's why I beat you", or, even lamer, "I am the Batman, I never give up, that's why I will beat you !" and he surprises Spider-Man with a hard uppercut that knocks Spider-Man unconsciousness.
Fact is, Batman can never beat Spider-Man, unless the (sigh) prep-time plays a large role in the fight. Maaaaaaybee, in that case, Batman has a chance after all. Without prep-time : 0%.