"... that Cap has an edge on him, just a little, in hand-to-hand combat."
Where did it say this?
Batman simply acknowledges the man's high skill level ("You could beat me" is a different kettle of fish completely to "You will beat me") and then realises that rather than waste time with a pointless brawl, they could go do something intelligent and useful instead. *That's* the part I liked.
And I don't believe for a second that Cap has the edge on Bruce anyway. In WW2, some of the best fighters in the world weren't quite available as teachers, what with Japan and China being rather busy at the time.