S.L. Benfica 2015, Benfica reported to have 246,401 members; however, after a scheduled renumbering by the club in August 2015, the number decreased to 156,916. In April 2017, Benfica reported they had a total of 184,264 members by 31 December 2016. Benfica has rivalries with Sporting CP and FC Porto, with whom it forms the "Big Three": Portugal's most decorated clubs. None of them have been relegated from the Portuguese league since its establishment in 1934. As Lisbon-based clubs, Benfica and Sporting have shared a rivalry for over a century; it all started in 1907 when eight prominent Benfica players defected to
1984–85 S.L. Benfica season won all league matches in April. In the Supertaça Cândido de Oliveira, a one-nil win for both Benfica and Porto forced a replay of the competition. In early May, John Mortimore was confirmed as new manager, with Csernai still in charge for another month. Before the end of May, Benfica lost away in the first leg of the Supertaça to Porto, but won the Derby de Lisboa with Sporting by 3–1, reducing the distance between them. In June, Benfica lost again in the Supertaça, losing the competition and finished the league in third place, 12 points behind Porto and five