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
1983–84 S.L. Benfica season Alvalade being eliminated by Sporting. In February, Benfica lost points again in the league after twelve consecutive wins. March was even more troublesome because the team was knocked-out of the European Cup by Liverpool, while in the league, Porto gave them their first league loss all season. Still, in the following month, Benfica won five games and draw one, allowing them to keep the three point lead over Porto. On 29 April, Benfica unexpectedly lost 4–1 with Vitória de Guimarães. The loss did not cause major damage because Porto had also lost points, so the distance was only cut to