The Belfast super featherweight, who fights out of Evolution Boxing Club in Carrickfergus, outscored Magnesi on the undercard of the Joseph Parker v Joe Joyce PPV at the AO Arena on September 24.
Commenting following the bout, Cacace’s trainer, Iain Mahood said: “We knew Magnesi was going to be there infront of Anto all night and would make a good attempt to break Anto in the early rounds.
“Heading into the last half of the fight was where we had planned to up the pace and start to dominate the rounds and bring Magnesi into deep water.
“I and the rest of the team in Michael Hawkins jnr and Andy O’Neill knew than when it came to the crunch, Anto can dig and hold out longer than anyone and now he is the best in the world.
“Many doubted the ability, but hopefully now everyone wakes up. There have been many who have tried and failed at world honors since the Frampton days, but there was only ever going to be one man and one team for the job and our team was solid.”