Saitama vs. Rick Sanchez

Random encounter on a street, Saitama kills Rick accidentaly because of some groceries discount or something during some sales at the market. The starting scenario doesn't really matter, it's just that Rick is killed by Saitama and is now preparing with weapons etc. Rick has Phoenix Protocol and prepares himself with all kinds of weapons and he comes to Saitama. The serious fight is on a normal street near the groceries store. I have no idea how this would end. But Rick wants to kill Saitama but Saitama doesn't take the fight serious at first because he thinks he is fighting an old man with sci fi tech.