Yeah, I was playing my new favorite game Injustice: Gods Among Us, I was playing as Batman, fighting Raven, and she is HARD as heck! Beating me some times that I didn't count, maybe I'm just not skillful at fighting, and wouldn't say she's better than Batman actually. So finally, I beat her, and start doing my own things.
-He has experience. Decades of disciplining mind and body.
-He knows how to get inside someone's head. He's completely demoralized opponents, taking them out of the fight, before a single punch could be thrown.
-He's gone up against ancient evils. The immortal R'as Al Ghul, is probably the only one who can compete in matching wits with Batman, and he's several centuries old. But at the end of the day, even he can't beat the bat.
-He doesn't rely on his gimmicks. They just make his job a bit easier. Take away his toys and costume, and he's still Batman.
-Another credit to Batman's skills, is that he has regularly turned a foes greatest strength against them, defeating them with it.