User blog comment:Captain James Rogers/Justice League V.S. The Avengers/@comment-4651179-20121215061659/@comment-4651179-20121216161224

But the serum made Steve Rogers be at the peak of human physic, thing Bruce Wayne trained to be. So Captain America is not really a SUPER-human.

Oh, I crossed out second because their actual first encounter was during Marvel vs. DC, but apparently in Avengers/JLA they didn't met yet.