Putting Naruto against Goku is like putting a flame thrower against a leaf, it's stupid as fuck and the outcome is obvious.
As for Saitama, that's really different. In all seriously, Saitama is going to win, because it's a gag on overpowered characters, and has that whole thing behind him. IN other words, no one can really beat him, because he'll be overpowered on purpose because he's kinda a gag character. The fact anyone can seriously take everything in OPM and put into a serious, debated discussion, is hilarious. They might as well scientifically explain why Bugs Bunny can beat up the ninja turtles...