Juan Diaz is the Captain and top scorer of the Argentina team.

At first Diaz is arrogant and conceited, but he is somewhat humbled after his match with Japan and duel with Tsubasa Ozora. Diaz is very talented and has been deemed to be the next generation superstar of Argentina Soccer, even being compared to Diego Maradona. Because of their talents and similarities he has developed a rivalry with Tsubasa of Japan.

Diaz's name is a reference to Ramón Ángel Díaz, however his character is based almost completely in Diego Armando Maradona.