Batman has been written up to the point where no human can beat him in a straight up fight. He fought Karate Kid a few years back (not Ralph Macchio) and defeated him. Karate Kid is from the future and knows martial arts from around the galaxy. read more
Karnak is supposed to be better than Batman in every way except gadgets and tactical mind in fights, but Karnak lacks any good showings against somebody like Batman, so I would give the win to Batman, specially with no rules and gadgets. read more
Batman has lost many times to normal dcu martial artists who have no meta abilities so Karnak's martial arts skill plus his ability would mean that it would be one fight that Batman couldn't win. If you had said to me Lady Shiva or Bronze Tiger in a similar scenario then maybe, but not batman. read more