You're about to watch the greatest sack of NFL player Marcell Dareus' career ... his total takedown of a TMZ employee using his superior NASCAR knowledge.
Dareus appeared on the "TMZ Sports" TV show and opened up about his newfound love of NASCAR ... when our resident TMZ NASCAR know-it-all jumped in and began to riff with him.
Here's the problem ... dude didn't know what he was talking about and Marcell called him out on it HARD in front of the entire newsroom.
Check out the clip -- it's all in good fun, freakin' hilarious and features something you thought you'd never see in your life ... two black dudes talking about NASCAR.
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