sentences:  1958 saw a League of Ireland side enter European competition for the first time with Shamrock Rovers going out 9–2 on aggregate to Manchester United in the first round of the European Cup.In the 1960s Waterford United became one of the league's most successful clubs as they won three titles during the decade, though Shamrock Rovers were the team of the 60s.The Hoops won six FAI Cups in a row during the 60s, a feat that has never been repeated.