At international level, he represented the Italy national football team at the 1962 FIFA World Cup.

[1][2] Mattrel played with Juventus for most of his career, between 1955 and 1965, aside from two brief loan spells with Anconitana and Palermo.

With the Turin club, he won three Serie A titles during the 1957–58, 1959–60, and 1960–61 seasons, as well as three Coppa Italia tournaments in 1959, 1960, and 1965.

[1][2][3] Regarded as one of the best Italian goalkeepers of his generation, Mattrel was as a serious, hard-working, and disciplined player, who was capable of organising his defence well.

Despite not being a particularly strong, acrobatic, or athletic keeper, or a good puncher of the ball, which saw him struggle on crosses, he was known however for his shot-stopping ability, excellent positional sense, speed when rushing off his line, and his ability to read the game, as well as his agility, in spite of his tall, slender frame.