During the second leg of the European Cup Winners' Cup semi-final in 1983, Kennedy picked up a serious knee injury after catching his studs at the edge of the pitch. Having played in every game of Aberdeen's European campaign up to then, he was forced to watch from the dugout when his colleagues faced Real Madrid in the final in Gothenburg, Sweden. The Dons lifted the trophy after a 2–1 victory over the Spanish giants. Kennedy earned himself a place on the substitutes bench, despite being unable to play, thanks to an act of respect from his coach Alex Ferguson. The injury proved so serious that he never played professionally again.