1983–84 S.L. Benfica season left the club in second, a point shy of the leader Porto, their next opponent. In the Clássico, Benfica beat his rival Porto and assumed first place. Later in the month, Benfica defeated Olympiacos in the second round of the European Cup, qualifying for the quarter-final. In November and December, Benfica won all their league matches, but lost the Supertaça Cândido de Oliveira to Porto. Benfica kept on winning in the Primeira Divisão in January, lapping the first part of league with a three-point lead. However they suffered a set-back in the Taça de Portugal, losing 2–1 in Estádio de
1985–86 S.L. Benfica season match with Salgueiros, which had been postponed in February because of the pitch conditions. They drew 1–1 and lost points in title race. In April, Benfica received Sporting in what was labelled the D-Day for the league. Despite leading the league for most of second round, they lost 2–1, which allowed Porto to catch them in the first place, with a better head-to-head record. Mortimore said: "Sporting had two chances and converted them both, we had lost the league". On the last day of the campaign, Porto beat last classified, Sporting da Covilhã and won the league, while Benfica lost