In the 2017–18 UEFA Champions League group stage, Atlético did not advance and dropped to the 2017–18 UEFA Europa League. In January 2018, Diego Costa returned to Atlético from Chelsea. On 16 May 2018, the team won the 2018 UEFA Europa League Final against Marseille. Simeone was sent to the stands in the first leg of the semi-finals against Arsenal and was suspended. He was forced to watch the second leg and final from the stands.