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
1990–91 S.L. Benfica season attentions were pointed on the league title. A strong campaign witnessed Benfica overtake Porto in February and then close the title with an away win in the Clássico, a controversial match because of the tactics employed by Porto to destabilize the team. On late May, Benfica secured their 29th league title, while Rui Águas won the Bola de Prata for league top-scorer. Benfica started the new season after having lost their fifth European Cup Final in the past season, while Porto regained the league title back. Swedish manager Sven-Göran Eriksson made some squad adjustments, releasing established players like Fernando Chalana,