We need a One Punch Man spin off featuring this character as the main protagonist.
You know who could beat Saitama?
Two-Kick Guy. He beats all of his opponents in two kicks, which leaves a lot more room for flashy fights rather than just one dumb punch. Also if he really wanted to Two-Kick Guy could dropkick Saitama, hitting him with both feet at the same time for an instant guaranteed KO.
Saitama is weaksauce.