He was so inexperienced that when he competed at the 1948 Olympic Games, he fouled in the shot put because he did not know that it was forbidden to leave the throwing circle from the front. The final events began so late that the field had to be illuminated by automobile headlights. A few minutes after Mathias became the youngest winner in men's athletics history. When he was asked how he intended to celebrate his victory Mathias replied, "I'll start shaving, I guess." Four years later, at the 1952 Olympic Games in Helsinki, Mathias broke his own world record and became the first repeat winner of the decathlon.