Hmm, well first what are the stakes ? If they are just sparing (like above) I can only see it lasting a short time and ending as this did. You must have the old,"heroes mistakes heroes for a villain melee ensues". They would have to mean it. I am with cap. Less baggage. Cap can fight dirty,he knows the moves and how to use it. If you will recall he once went undercover as Crossbones at one point and had to "fight like him,which means alot dirtier."