Michael Jordan's son, Marcus, says he once WHOOPED his dad on the court in a game of 1-on-1 ... and he's telling TMZ Sports all about the huge accomplishment!!!
Marcus -- MJ's 2nd son -- says he used to play a modified version of 1-on-1 called "Cutthroat" with his dad ... and one day, he actually came away with a WIN!!!
"I had a quick victory," Marcus tells us. "I can't remember the score, but I did win."
So ... how did the G.O.A.T handle it?? Exactly like you'd expect.