If you leave the battlefield, that should count as a KO.

Byrne's Batman threatened to kill an innocent if Superman tried touching him. The innocent was Batman, but he still made the threat. Loeb's Batman (yes, Loeb, I know, I know!) used Lois Lane as a hostage to force Superman to come to his senses. Waid's Batman had contingency plans for all his friends. Rucka's/Johns'/"DC's" Batman used a spy satellite to track all the metahumans in the DCU.

The ruthless, win at all costs Batman has been pretty well established by multiple authors for about 25 years now, even discounting Miller. He won't go through on some of his threats - killing Lois Lane, for example - and sometimes his threat isn't quite what it seems (Batman was willing to kill an innocent to stop Superman - namely, Batman was willing to kill himself). But he's still pretty ruthless and I don't think, in most interpretations of the character, that he'd play fair with, well...anyone that he was opposed to in some way.

Cap, he just doesn't know how to lose.

Like when he gave up at the end of Civil War?

Not knowing how to lose really isn't something Cap has up on Batman.

Except it birthed one of the most misinterpreted lines in comic history.

It's conceivable that everyone could understand what it means, Realmser...but it would take a very long time. Tell me this, though...do they want to?

something to consider abut that line In JLA/Avengers.

Batman is all about bluff and intimidation. It could very well be interpreted as 'Im going to get my arse handed to me, but I cant let him know that I believe that...soooo "You may beat me, but it will take a long time... (which is no doubt a true statement)...But do you want to (hey cant we talk about this and you will realize Im not a bad guy...I sense a fairness in you...lets work together)

Lets not assume Batman would speak literally

I will choose Cap.

Batman's appeal were that he doesn't have any power but he was considered to be equal to Supes or any other, just with his gadgets and brain (well... and money) safe the day. But after DK, anyone thinks that Bats it's like a sarchastic swiss knife or something... i think that's must childlish than a dude flying around on his underwear.

Cap's still the same, the time have changed but he defend his believes. And if he have to take on the bat, he will put 101% more effort on the fight, and that will make him the winner.

I tend to interpret lines at face value -- especially in a relatively subtext-free medium such as the funnybooks.

And Cap fell for it! Batman wins again!

I'd cheer for cap, but I think I'd be disappointed in the end.

It's because of this that Batman would win. His healthy respect of his oppponents drives him to find a way to defeat them. Batman won't underestimate Captain America. I'd love to see Cap win, but Batman is far more the detective than C.A. He'll find a way to beat him. Heck, Batman has found ways to beat Superman. He's worn Kryptonite gloves, tied Supes up with Wonder Woman's lasso, put him under a giant red light ... he'd find a way to beat Cap.

And the other thing is that if you're going to interpret a line, you should actually know what it is first (or the gist of it, anyway, which is not "Cap would win").

Batman relies on gadgets and preplanning.

Cap just kicks ###.

On the first phases of the fight, it would be a tie.
Batman's skills and gadgets stall him against Cap's physical superiority.
But if the fights goes too long, Captain America will win, he is simply stronger, more durable and possibly more agile, and can maintain that level far longer than Bats.

After all, Batman is an human, Captain America is an super-human.

I voted for cap because he is my favorite one. but if you look at the DC vs Marvel universe mini series that led to the AMALGAM books you will find that when they had the pairings the every one had a clear and quick winner with each fight lasting 1 or 2 pages save for one. the Cap vs Batman fight that basically lasted for one whole book, once you put all the parts together, with no clear winner save that bats was breathing hard.