Balotelli was touted as one of football's brightest talents during his time at Inter under legendary manager Jose Mourinho between 2007 and 2010.
While he was a talent, the Italian striker had his fair share of bad moments off the pitch in the past, most notably clashing with Jerome Boateng during his time at Manchester City.
"I gave him a good beating, it's true. I love Mario, but he really deserved it that day," Materazzi said on Instagram Live, as per the Sun.
"We've become friends again now, practically brothers, but he did something that day that he really should not have done.
"Throwing his shirt to the ground after the final whistle wasn't even the worst of it. Before the game, on the team bus, he told us: 'Today I'm going to play badly,' so I promised to make him pay if he did.
He added: "When he came off the bench, he tried a shot from midfield rather than go on the counter. Diego Milito wanted to kill him.
"We believed in Mario, he scored many goals and contributed to the victory, but a week after that, I asked Mourinho to put me against Balotelli in the training ground games between ranks. After a few seconds, I'd send him back to the dressing room.
"I really loved his father, as after a game with Rubin Kazan he told Mario: 'I didn't like your performance, you have to play more for your teammates. And stop going around with girls!' What an idol."