Partey signed a contract extension with Atlético Madrid through 2022 on 14 February 2017. On 31 October, he scored his first European goal with a long-range strike to equalise at home to Qarabağ in a 1–1 draw in the Champions League group game; he became the first African to score in the competition for Atlético. Following his impressive performances for the club, he was rewarded with another contract on 1 March 2018, this time until 2023. On 16 May, he played in the 2018 UEFA Europa League Final, as his side won 3–0 against Marseille.