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
1974–75 S.L. Benfica season 1–0 and dropped to third place, two points shy of leaders Porto and Guimarães. They reacted positively to the loss and won their next four Primeira Divisão matches, retaking first place albeit shared with Porto. Both had 18 points. In Europe, Benfica qualified for the quarter-finals, after eliminating Carl Zeiss Jena in the second round. Off the field, Benfica lost Eusébio to injury, as he underwent his six operation to his left knee. On match-day 12, Benfica drew 0–0 with Oriental and dropped to second, a point from leaders Porto. In the final three matches of December, Benfica won the