Spike is a close combat specialist, it’s not as unfair for him as it is for Mumen, who obviously can’t do anything at a range against guns.
Which superhumans has he fought ? I don’t remember anyone being remotely impressive outside of gun/martial arts skills.
I mean he can hit him all he wants it doesn’t matter if he can’t lay a scratch from him. In an audiobook Mumen fought a monster immune to firearms and did well. A single punch would splatter Spike.