On 26 September 2018, in his first appearance of the 2018–19 season, Emerson scored his first goal for Chelsea, the equaliser in an eventual 2–1 away win against Liverpool, in the third round of the EFL Cup. On 24 February 2019, he started for Chelsea in the 2019 EFL Cup Final on, and was one of the three Chelsea players to convert their spot kicks in the resulting shoot-out following a 0–0 draw after extra-time; however, Manchester City ultimately prevailed 4–3. On 29 May, he assisted Olivier Giroud's opening goal in a 4–1 win over Arsenal in the 2019 UEFA Europa League Final. On 17 March 2021, Emerson scored his first UEFA Champions League goal for the Blues in a 2–0 home win over Atlético Madrid in the second leg of the Round of 16 tie.