S1: SM is physically stronger, but his hits aren't doing significant to KCM's body when KCM can take a hit from Han to the face with only a bruise. The same can be said for SM. KCM doesn't have any super impressive strength feats that'd lead me to believe his hits will have SM Naruto curling in pain or anything close to that. KCM has more stamina though, and he's faster with better reactions. (but SM has far far better sensing) Meh, it could go either way. SM>>KCM in physical strength so I'm leaning towards him beating KCM down eventually.
S2: Chakra arms might give him the win. Hits would do some damage to SM's body while KCM can take Frog Kata without major damage. Only way SM wins is if he presses on KCM's body and uses the tech he used to push Obito's rods out of Son Goku to cause internal damage. If that's even how it works.