mason enjoyed his best achievement in the 1999 bdo world championship, when he recovered from 1–4 down in sets in his best-of-nine quarter-final match against martin adams, survived many match darts against him before eventually winning 5-4 in sets, winning by 6–4 in legs in the deciding set. this match is regarded as one of the best matches on television, and it included 29 180s between the players; 13 for mason and 16 for adams. he lost the semi-final 2–5 to reigning bdo world champion, raymond van barneveld, three of those sets on deciding legs.