Prendergats made his senior championship debut on 25 June 1978 in a 2-17 to 1-4 Leinster semi-final trouncing of Offaly. Kilkenny subsequently broke Wexford's stranglehold on Leinster and secured the provincial title with a narrow 2-16 to 1-16 victory. It was Prendergast's first Leinster medal at the highest level. On 3 September 1978 Kilkenny faced Cork in the All-Ireland decider, as the Rebels were bidding to become the first team in over twenty years to secure a third championship in succession. The game was far from the classic that was expected, with the decisive score coming from Jimmy Barry-Murphy whose low shot towards goal deceived Noel Skehan and trickled over the line. The 1-15 to 2-8 score line resulted in defeat for Prendergast's side.