9/10 to Steve.
I do believe Bruce would completly mop the floor with Steve if he wasn't superhuman.
But since Steve is pretty skilled himself, and that he got some heavy advantage over Bruce (don't fatigue, able to bench press 2 tons, faster than human speed, etc), I can only see Bruce winning with the "lucky punch".
Again, if it wasn't from the superhuman stats, I'd see Bruce completly owning Rogers.