|Saitama vs. Speed-o'-Sound Sonic|
|Outcome||Saitama is victorious|
|Hero Saitama||Villain Speed-o'-Sound Sonic|
|Saitama is uninjured||Sonic is hit in the crotch|
|Previous||Saitama vs. Hammerhead|
|Next||Spring Mustachio and Golden Ball vs. Kombu Infinity|
After defeating Hammerhead, Sonic attacks Saitama mistaking him for a Paradiser. Due to an injured pride, Sonic tries to kill Saitama for being able to see through his attacks. He showcases his speed, boasting how Saitama can't keep up with his speed, and tries to attack Saitama with his Wind Blade Kick. Unfortunately, Sonic is accidentally hit in the crotch by Saitama, ending their fight. The battle with Speed-o'-Sound Sonic lasted 57 seconds.
While writhing in pain, Sonic declares that he will take a leave from his mercenary occupation to train and asks for Saitama's name. Sonic states that Saitama his rival and declares he will one day kill Saitama. Saitama encourages him.