Paquetá made his club debut on 12 January 2019, playing 85 minutes before being replaced by Fabio Borini as Milan beat Sampdoria 2–0 in extra time in the Coppa Italia. Four days later, Paquetá played in the 2018 Supercoppa Italiana, held at the King Abdullah Sports City in Jeddah, Saudi Arabia, where Juventus beat Milan 1–0. On 21 January 2019, Paquetá made his Serie A debut in a 2–0 win over Genoa at the Stadio Luigi Ferraris. During the match, Paquetá performed a 'rainbow flick' over opponent Daniel Bessa. Paquetá scored his first goal for Milan in 3–0 win against Cagliari, scoring the second goal. He dedicated his goal for the victims of a fire at his old club Flamengo, all members of the under-15 team.