His first appearance of the 2005–06 season came on 29 November 2005 against Reading in the Round of 16 of the League Cup, starting the whole game, in a 3–0 win. He then played in the third round clash with Cardiff City. Djourou made his full Premiership debut for Arsenal in the 7–0 victory over Middlesbrough on 14 January 2006, playing at centre-back with Philippe Senderos. He started Arsenal's FA Cup fourth round clash with Bolton Wanderers as part of a makeshift defence, a game in which Arsenal lost 1–0. In February 2006, Djourou played in the league games against West Ham United, Birmingham City and Bolton Wanderers. After a five match absence, he returned to the first team, coming on as a substitute against Aston Villa in Arsenal's 5–0 victory, replacing the injured Emmanuel Eboué. Djourou then started in a league match against Portsmouth on 12 April 2006, a game which also saw the comeback of Sol Campbell, in a 1–1 draw. At the end of the 2005–06 season, he went on to make twelve appearances in all competitions.
