Randy: Listen, we got two more in the backseat... Two-Bit: (busts a soda bottle and giving it to Ponyboy, then snaps open his switchblade) Well, pity the backseat, pal!
In the movie, he breaks his bottle on a chain-link fence, whirls around to give it to Ponyboy, pulls out his blade, and holds it up to the Soc's throat, 'all in the space of two seconds. That guy may be a joker, but cross him, and you are screwed.
The climactic rumble scene, in both the novel and the movie.
And yes, the Greasers did come out on top. Ponyboy sure takes a beating, but he definitely helped Dally, who threatened the nurse with a switchblade to be there.
Ponyboy: You know what a Soc is? White trash with mustangs and madras. (spit)
Two-Bit calling out Johnny's mother in the movie, telling her to go straight to hell.