No way Koro beats Saitama.

Is that serious? Saitama wouldn't lose to Koro Sensei or screw, first of all Saitama could obliterate Koro if he wanted to and even Bang could defeat Koro if he is serious, and let's say that Saitama's vigor is basically limitless

the one time i can think of Saitama losing and the story being better for it! a good oneshot!

pretty good.
Bang can takedown Saitama using martial arts even when he is taken by surprise.
i can see this spar happen in canon.

FYI, Saitama is shown to move at 50 times the speed of sound

You do realize that this story is shit?
Saitama woulda insta killed him if he was serious. He could destroy the WORLD with a single punch if he really wanted to (translations differ in the manga, so he can either end all life with one punch or destroy the planet). Along with that, I’m pretty sure that Saitama is faster than Koro Sensei.

This. This is the best story I've ever read. Thank you.

You made a believable fight in which Saitama loses, now that's something to be proud of!

Aw, that’s cute. I’d like to see exactly what Saitama does in this more serious training. Great crossover!

I was kinda hoping for a curbstomp battle between saitama and Koro-sensei but this was 20x better and a really good read.

i think saitama is too simple minded and he wont even notice that koro sensei is a monster

I liked this but as many others say, Saitama was a lot depowered (or how ever you say it) I would like note of this though, it's good

Wonderful story!

What training from Genos?

Way to go. This was well written. Aside from a few spelling errors, it was flawless.