Leicester-born Duffy was one of a number of teenagers who were given a shot in the Leicester first team by manager Jock Wallace, who was keen to add youthful exuberance to his team towards the end of the 1970s.
He had a decent scoring rate at youth team level and actually found the back of the net on his debut with a header but saw that chalked off by the officials.
Duffy provided the assist for Gary Lineker's first-ever City senior goal and he scored what turned out to be his only Football League goal on the final day of that season at Sheffield United, when Leicester fielded their youngest-ever side.