Waka Flocka Flame -- OWNED by Little Kid ... With Mad Mario Kart Skills

Waka Flocka Flame grew up on video games ... but he just met his Mario Kart match -- a 9 year-old boy who LOVES talking crap after beating his ass!

Waka hit up an event for Project Cry No More Wednesday in Compton ... and that's where the rapper was challenged.

You gotta watch the video -- the 9 year-old is not impressed he's going head-to-head with a famous rapper ... he's way too busy dodging bananas and doling out red shells.