One Punch Man Manga Chapter 44

Speed-o’-Sound Sonic brags that he can defeat both Genos and Saitama, but Genos shocks him with superior speed and slices off his topknot. Their intense battle escalates until Saitama intervenes to prevent Genos from destroying the surroundings.

When Sonic unleashes his ultimate technique, Saitama casually counters with Serious Side Hops, moving so fast that Sonic is completely overwhelmed. Sonic ultimately retreats, while Fubuki witnesses the scene and finally understands the terrifying extent of Saitama’s true strength.