Spoiler Summary [Click to show or hide]:
One Punch Man Manga Chapter 14 marks the first fight between Saitama and Speed-O-Sound Sonic and thus ushers Sonic’s hate (or respect) for our One Punch Man!
But before that, Hammerhead encounters Saitama after running away from Sonic in the previous chapter.
He attacks Saitama with a strong punch followed by his ultimate maximum technique but ends up beaten after Saitama destroys his black suit with one punch.
After escaping for his life, Sonic showed up and attacked Saitama twice- first with a kunai and second with a blade. Both were useless against our Sensei, which forces Sonic to release his ultimate move to eliminate Saitama.
The Chapter ended with Hammerhead lying face down on the grass after two robots attacked him.