|Episode 9 - Unyielding Justice|
Saitama was asked by the administration to help take down this high level Deep Sea King.. they already know there's more to him than people assume.. and by that point, Genos was already fighting the monster toe-to-toe, and was holding his own against him, until he had to jump in front of an acid attack to save a little girl...
Then Mamen Rider, the fearless but weak hero at the top of the C class, jumps in to try fighting, and is completely useless... all the civilians are cheering him on regardless... Saitama shows up just as Rider and Genos are about to be finished off...
The civilians actually recognize him now, as the rank 2 C class hero, and one of them points out how the monster's direct punch to his head didn't even affect him. Everyone cheers when he defeats the monster in one punch...
"Huh... that was lame. I had my hopes up."
later, Saitama opens his first fan letter.. from someone calling him a rotten cheater.
It shows what happened after the monster was killed. One civilian claimed Saitama must've cheated, or that this monster wasn't very strong at all... Saitama just laughs, and tells them that he was able to beat the monster only because the other heroes had worn it down so much, and he just took the credit for it.
... however, he did get another letter saying thanks for saving him... it was from Mumen Rider.
The association moved Saitama up to rank 1 of class C, and had a meeting to consider moving him up to class B... They said the rumors about him cheating were just rumors, and that if he really is cheating, he won't make it through the B class that way.