 He made his full debut for Aberdeen in 1979 at the age of 17, and by the 1981–82 season had become a regular in the side.in January 1982, Hewitt scored the only goal of the game in a third round Scottish Cup tie against Motherwell.This goal, timed at 9.6 seconds, was not only the fastest recorded in Scottish Cup history, but proved to be the first step in Aberdeen's route to the following season's European success; the club qualified for the Cup Winners' Cup by going on to win the Scottish Cup that season.