We have to consider MANY things like something being super ability/resistance rather than a skill feat, the resistance to precog or pressure points on cellular level for example. Your capability of delivering/blocking attacks in clever way and outpacing your opponent in battle with considering your fighting styles, choosing the response to attacks, I believe that is skill, not really "he is the greatest swordsman in the world and has outskilled this guy" or "he controls his body on sub-quantic level to deliver a devastating blow through skill", it's best to know what impressive FIGHTING feats they have. Let me show few,
Saejima vs Majima,
Kiryu vs Shibusawaor
Snake vs Liquid . Something being flashy not always translates into skill.
@Planck
When did I tell something about AP. Cellular level pressure points are completely supernatural, just like abiltiies like ice manipulation, heat manipulation et cetera. Not necessarily skill feat, it requires some degree of knowledge on human anatomy and where to hit but that's basically it for this level of a character.
The rest? We need to know how they did it to consider it skill. There's no such thing as outskilling a guy who's literally you, though you can outmatch him in combat in a way. That doesn't mean you are far more skilled, no, you are AS skilled as the guy. When you defeat your equal that doesn't
always make you better than him. There are many factors influencing the fight like stamina or speed. Fighting someone completely equal can't end in inconclusive, even if you fight someone same as yourself.
Composite Human is culmination of BILLIONS people, with millions of actual martial artists mastering styles in their own way or masters of mathematics, physics, biology, science. He does not have any superpower, supernatural agility or supergenius intelligence, I believe that's why people underestimate him sometimes. But not necessarily everything needs to be considered a "skill feat" in battle. Well, knowing how to use your capabiltiies in battle is quite a feat, but I have seen people sometimes stating raw stats = skill...