Middlesbrough needed extra time against Brighton & Hove Albion in their first game, and later advanced on penalty shoot-outs against top-flight Everton and Tottenham Hotspur; they then won home and away against league leaders Arsenal in the semi-finals.

Kevin Davies got a goal back in the first half after an error by Boro goalkeeper Mark Schwarzer, but Middlesbrough kept the score at 2–1 for their first major trophy.

[6] In the next round on 28 October, they again hosted a second-tier team, this time Gillingham, and won 2–0 with goals by Stelios Giannakopoulos and Henrik Pedersen, in front of a notably low crowd of 5,258.

Youri Djorkaeff would have put Bolton back into the lead, but referee Mike Riley disallowed it for an earlier handball; they scored minutes later from Jay-Jay Okocha's free kick.

[12] In the next round, they travelled to Wigan Athletic of the First Division and won 2–1 with Massimo Maccarone and Gaizka Mendieta's first goals of the season, despite the hosts at the JJB Stadium scoring a late free kick through Jimmy Bullard.

After 120 goalless minutes, the match went to a penalty shoot-out in which Mendieta scored the winner after Middlesbrough goalkeeper Mark Schwarzer saved from Leon Osman.

The shoot-out, in which Schwarzer denied Mauricio Taricco and Kasey Keller blocked from Mendieta, went to sudden death, in which Middlesbrough's goalkeeper saved from Gus Poyet and Franck Queudrue scored Boro's winner.

In the first leg at Highbury on 20 January 2004, Queudrue exploited a mistake by Arsenal defender Martin Keown and passed to Mendieta, who then assisted Juninho for the only goal of the game.

With five minutes remaining, Arsenal's José Antonio Reyes scored an own goal by deflecting Stuart Parnaby's shot, making Middlesbrough advance to the final 3–1 on aggregate.

[20] Mendieta's pass let Zenden run down the left wing and cross for striker Joseph-Désiré Job to put Middlesbrough ahead in the second minute.

[22] McClaren praised his goalkeeper Schwarzer for recovering from his error that allowed Bolton's goal, in order to make saves that won the match.

[25] Columnist Henry Winter The Daily Telegraph wrote that it was the best League Cup Final since Luton Town beat Arsenal in 1988.

[26] He praised all four of Middlesbrough's back line for their "alert defending", and noted the hard work in midfield by Boateng that allowed Zenden, Juninho and Mendieta to create chances.

[26] Alan Smith of the same newspaper opined that 33-year-old Southgate was the most deserving winner, as reward for his consistency since arriving in an "average" Boro side in 2001.