The Biebs knows how to throw down!

Justin Bieber has clearly picked up a couple pointers from his friend Floyd Mayweather, because the singer got into a fist fight last night with a guy more than double his size and managed to hold his own!

JB was outside his downtown Cleveland hotel around 11pm after catching game 3 of the NBA finals when he had some words with a massive bro, and when the guy threw a punch at him, he hit back before bystanders broke up the brawl.

The "Sorry" crooner was clearly not sorry about his actions, and took to Instagram to brag about his lack of injuries! "Not a scratch on this pretty boy," he captioned a photo of his bruise-free face.

We have a feeling a lawsuit is coming...