FC Porto the 1955–56 Primeira Divisão on head-to-head advantage over runners-up Benfica. Later that season, Porto beat Torreense to win its first Taça de Portugal and achieve its first double. As the Portuguese league winner, Porto made its debut in European competitions by qualifying for the 1956–57 European Cup. The club's first participation was short-lived, ending in the preliminary round with two defeats against Spanish champions Athletic Bilbao. A year later, Porto lifted its second Taça de Portugal by beating Benfica 1–0 in the final. The two clubs met again in the following season's final, but this time Benfica took the trophy
FC Porto in international football competitions losing the 1964 Portuguese Cup final against champions Benfica. Porto progressed from the first round of a European competition for the first time, after a 4–0 aggregate victory over French Cup winners Lyon, but fell in the next round to 1860 Munich.<ref name="1964/65"></ref> At the end of that season, Porto finished runners-up to Benfica in the league and qualified for the following season's Fairs Cup. The club's performance was similar to that of the previous campaign: a first-round elimination of a French team (Stade Français) followed by a second-round loss to a German team (Hannover 96),<ref name="1965/66"></ref> which included a