It was in the training battle Deku and Bakugo vs All might as All might was saying things to Bakugo

All might: Why can’t you just accept Young Midoriya’s help?

Bakugo: I’S RATHER LOOSE THAN ASK FOR DAMN DEKU’S HELP!

All might: Why is that?

Bakugo: Bc i said so

All might: You were friends with Midoriya back then

Bakugo: No

All might: Yes you were

Bakugo: No I wasn't-

Deku: Run and punch Bakugo in the face making Bakugo fall on the floor Sick of your SHIT!