Aké made his Premier League debut on 26 December 2012 against Norwich City as a 17-year-old, replacing Juan Mata in added time at the end of a 1–0 win at Carrow Road. He made his first start for the club in the FA Cup on 27 February 2013 in a 2–0 win against Championship team Middlesbrough. He was chosen to start in a defensive midfield position for Chelsea in the second leg of their UEFA Europa League quarter-final clash with Rubin Kazan in Russia on 11 April, a match that finished in a 3–2 loss but resulted in a 5–4 aggregate victory. Aké was an unused substitute for Chelsea in the Europa League final against Benfica at the Amsterdam Arena on 16 May, which Chelsea won 2–1. He was voted Chelsea's Young Player of the Year on 16 May, and made his first Premier League start three days later in the 2–1 win against Everton at Stamford Bridge on the last matchday of the season.