Floyd Mayweather's mixed up in another one-sided fight, but he wasn't the one throwing punches ... some guy in his crew delivered this beatdown.
The champion boxer was involved in an incident at a Las Vegas mall on Thanksgiving eve that resulted in a fan getting thumped by a presumed member of his security team ... as you can see on surveillance footage, obtained by TMZ Sports.
We're told Floyd was exiting the House of Hoops store with his girlfriend and his crew when an employee working at one of the kiosks nearby approached for a photo.