Mayweather, 40, took on the UFC’s lightweight champion in a multi-million-pound boxing match in August 2017.
McGregor entered the bout with no professional boxing experience to his name but acquitted himself well in the early rounds of the much-maligned ‘Money Fight.’
Fatigue soon overwhelmed McGregor, which paved the way for Mayweather to register 50th professional victory via a tenth-round TKO.
“Shin bone to the cheek bone (sic),” the accompanying caption read. “The rule set kept you out the funeral home.”
Somewhat surprisingly, Mayweather refrained from firing back at his most recent opponent.
However, ‘Money’ took aim at McGregor on Wednesday night in an Instagram post, which referenced the UFC superstar’s alleged run-in with a man with connections to Ireland’s criminal underworld.
“I already f**ked you up in 2017 now they about to f**k you up in 2018,” Mayweather wrote.
“You’re about to start your new year off with a bang.”