Cap has super soldier serum in his veins. And while Batman may be amazing but he isn't a super soldier. Hand to hand its Cap but because of the intelligence of Batman i think he'd try to keep his distance and come out on top with his gadgets and strategies. Quick side note. Not sure if anyone is into Deadliest Warrior on SpikeTV but if they ever did a season or at least a couple episodes where they had Marvel vs. DC and other franchise icons go at it that would be amazing. At least in my opinion.