Mazzilli was a part of Argentina's gold medal-winning team at the 2016 Olympics. At the 2012 Summer Olympics, he competed for the national team in the men's tournament. He has won the bronze medal at the 2014 Men's Hockey World Cup. In July 2019, he was selected in the Argentina squad for the 2019 Pan American Games. They won the gold medal by defeating Canada 5-2 in the final.