Flack reached Athens after an uncomfortable six-day rail and sea trip, during which he was plagued with sea sickness. On the opening day of the Games he won his first race, the first heat of the 800 metres run, finishing in a time of 2 min 10.0 sec. On the second day he lined up against the American favourite, Arthur Blake, in the 1500 metres run. Running shoulder to shoulder with Blake in the final straight, Flack powered ahead near the end to win by more than five metres in a time of 4:33.2. On the fourth day of the Games, Flack earned his second first-place medal, winning the 800 metres in 2 min 11.9 sec.