Sorry but even though saitama does show unexplainable strength and speed he doesn't have the strength to blow up a universe... no matter how physically strong he is he will never surpass goku in super saiyan 1,2,3 or God or SSG Blue, if it was a hand to hand battle he might be able to win but then again goku also knows martial arts.

Saitama needs oxygen to breathe so if goku decides to blow up earth it would be the end of Saitama...

Saitama is more of a satirical idea than a person. That's why he would beat Superman, The Hulk, and yes, even Goku. The idea of One Punch Man is that he can beat ANYTHING in a single punch. He's a joke. A very, VERY powerful joke (and a VERY funny one might I add).

Both anime defy logic but if we go according anime rules then Saitama can defeat ANYONE with one punch. I agree with @AuraMaster