 By 1974 Fennelly had joined the Kilkenny under-21 team and was captain of the side.He won his first Leinster medal that year as Kilkenny accounted for Wexford by 3-8 to 1-5.The subsequent All-Ireland decider against first-time finalists Waterford was a close affair, however, at the final whistle Kilkenny were the champions by 3-8 to 3-7.