The season ran from 1 July 2004 to 30 June 2005; Benfica competed domestically in the Primeira Liga and the Taça de Portugal.

The club also participated in the UEFA Champions League as a result of finishing second in the Primeira Liga in the previous season.

José Antonio Camacho led Benfica to another second-place finish and broke an eight-year title drought; he attracted interest from Real Madrid, who signed him in late May.

Benfica signed more players than the year before, but only Quim, Manuel dos Santos and Azar Karadas became regular first-team fixtures.

Domestically, Benfica started the season with consecutive wins, rising to the top of the table by early October.

[2] Benfica looked for replacements with the same profile as Camacho;[3] they offered the position to Luiz Felipe Scolari, according to his agent.

[7] Negotiations with Fernández failed,[8] but on 17 June, club president Luís Filipe Vieira announced that Benfica had signed a new manager but did not name him.

[11] The 65-year-old Italian started his managerial career in 1974 and came to recognition at Juventus, where he became one of Italy's greatest managers, the only one to have won all UEFA club competitions and the Intercontinental Cup.

[13] In the transfer market, the most significant signings were of 28-year-old Quim, Portugal's second-choice goalkeeper, to compete with incumbent starter José Moreira.

[15] Benfica also signed Norwegian striker Azar Karadas after his compelling performance against them in the previous season's UEFA Cup with Rosenborg.

[17] Other than him, only Armando Sá and Hélder Cristóvão were regularly used, and both continued their careers abroad, with Villarreal and Paris Saint-Germain respectively.

[19] On 9 July, Benfica travelled to Nyon, Switzerland, for a two-week tour, where they played their first pre-season matches,[20] with wins against Real Zaragoza and Marseille.

[27] Benfica started their season with the third qualifying round of the Champions League, attempting to make their first presence in the group stage since 1998–99.

[41] On 19 September, Benfica travelled to Coimbra to face Académica, beating them 1–0 with a goal from Simão to reach the top of the league table.

[38] Benfica played against ten men throughout the second half, securing a win in the 91st minute when Geovanni converted a free kick.

[38] The match was notable for the controversy regarding Olegário Benquerença refereeing, with Porto winning 1–0 with a goal from Benni McCarthy.

"[50] The following Thursday, Benfica opened their UEFA Cup group stage campaign with a home win against Heerenveen.

[52] Three days later, Benfica started their Portuguese Cup campaign against the third tier club Oriental de Lisboa.

[33] Benfica visited Beveren and won 3–0 with a double from Zlatko Zahovič, ensuring qualification for the round of 32 behind Stuttgart.

[60] The visitors scored first, but Benfica responded through Simão with a double inside ten minutes, giving them the first league win in a month and returning them to first place.

[71] Trapattoni, in the preview for the upcoming match with Penafiel, said, "Benfica needs to forget this humiliating defeat quickly.

[74] On 21 December, Benfica played the last game of the year, hosting third-tier team AD Oliveirense for the Portuguese Cup.

"[76] In January, Benfica opened the month with a visit to the Estádio José Alvalade to face Sporting CP in the Lisbon derby.

[84] As the game went into extra time, Paíto and Simão both scored in individual efforts, bringing the final scoreline to 3–3.

[89] Trapattoni was happy with the draw, saying Benfica entered a little nervously and were lucky not to lose in some random event, like in past games.

"[100] Three days later, on 6 March, Benfica played at Estádio da Madeira against Nacional and won 1–0 with a goal from Nuno Gomes.

Near the end, Quim brought down Wendel Geraldo inside the box but failed to convert the penalty, hitting the woodwork.

The high-pressure match was unlocked in the 83rd minute when Luisão jumped higher than Ricardo and headed in the winning goal.

[127] Two days after the defeat, Trapattoni confirmed he was leaving Benfica for personal reasons, ending his one-year tenure in Portugal.

Note 2: Players with squad numbers marked ‡ joined the club during the 2004–05 season via transfer, with more details in the following section.