Arsenal's 3–0 win at Fenerbahçe SK in the Champions League group stage play-off, playing the last three minutes in the place of Theo Walcott. On 26 September, he scored the deciding penalty in a shootout against West Bromwich Albion to send his team into the fourth round of the League Cup. Upon the arrival of Alexis Sánchez in the 2014 off-season, Monreal took the vacant number 18 previously worn by Sébastien Squillaci. On 23 August, he assisted Olivier Giroud's late equaliser in a 2–2 draw against Everton. Additionally, an injury crisis in the squad saw him being deployed in an unfamiliar central defender role in a string of games, after Laurent Koscielny was put out of action due to an Achilles tendon injury. On 9 March 2015, Monreal scored the opening goal in a 2–1 win over Manchester United at Old Trafford that put Arsenal through to the semi-finals of the FA Cup. He played the full 90 minutes in the decisive match, a 4–0 defeat of Aston Villa at Wembley Stadium. On 19 January 2016, Monreal signed a new long-term contract. On 23 April 2017, he scored the vital equaliser as his team came from behind to defeat Manchester City in the FA Cup semi-final at Wembley. On 6 November 2017, after good performances on the left side of a three-man defence, Monreal won the Professional Footballers' Association Player of the Month award for October of that year. The following 20 January, he netted once and made two assists before retiring injured 30 minutes into an eventual 4–1 home win against Crystal Palace. Real Sociedad Monreal returned to Spain on 31 August 2019, with the 33-year-old joining Real Sociedad on a two-year contract. He scored on his competitive debut two weeks later, converting an easy tap-in at the hour mark of an eventual 2–0 victory over Atlético Madrid at Anoeta Stadium. Monreal missed the entire 2021–22 season, due to a knee injury. On 23 May 2022, the club announced his departure. On 16 August 2022, Monreal announced his retirement at 36. International career In 2007, Monreal earned his first call for the Spain under-21 team. He started all their matches in the 2009 UEFA European Championship, in an eventual group stage exit. On 6 August 2009, Monreal was called up to the senior side for the first time, for an exhibition game with Macedonia. He played the last 15