Board Thread:Questions and Answers/@comment-75.142.99.93-20160607005127/@comment-27524064-20160709030911

You can't really prove whether saitama is weaker or stronger then any of those characters because he's never shown what he can do. Like I said before there is some cercumstancial evidence that he has no limit to his power, as honestly it would seem to go against everything weve seen in the story if metal bat could surpass him. But until we get something concrete either for or against it I don't think anyone can say anything for sure about him being stronger or weaker then Goku, usagi, superman or whoever.

What we do know is under the right cercumstances such as Zenko getting killed, bat could surpass goku in terms of brute streingth as his max potential power was stated to be nearly infinite in the data book. Goku might still win in a fight vs full powered bat as he has ki attacks, martial arts, etc while bat doesnt have invulnerability or a healing factor, but that isn't the point. The point is if Saitama has limits that means that he isn't unbeatable in his universe, and so far the point of the story seems to be that no one who has shown up in the story can touch him. Of course  this isn't solid proof but in terms of narrative intent there seems to be a lot going in favor of the theory that Saitamas power is beyond limits.