In his youth, Matthys was a gifted cyclist in the category of ’promises’, together with André Dierickx, which later won famous classics such as the La Flèche Wallonne, but a very serious accident during the last years of his humanities studies in Ghent and a long rehabilitation, gave his life a strong new direction.
Masson was Belgian road race champion twice, and won important races such as La Flèche Wallonne, Paris–Roubaix and Bordeaux–Paris.