[5][6][7] Coming through the youth ranks at Standard—where his father played until 2006[6]— Moreira first tried to leave the club in 2019 for personal reasons, training with Lierse Kempenzonen, but with the Belgian federation eventually not approving his move.

[12][13] He played a major role in the UEFA Youth League, where Benfica U19 topped their group against Dynamo Kyiv, Barcelona and Bayern Munich, Moreira most notably scoring a goal against the latter during a 4–0 home win in October 2021.

[19] On 30 August 2023, he made his debut for the club starting in their EFL Cup second round tie against AFC Wimbledon, featuring for 45 minutes in the eventual 2–1 victory.

[21] He made his debut for the club on 17 September, coming off the bench to replace Ernest Nuamah on the 77th minute of a 0–0 league draw at home to Le Havre.

[29][30][31] A left-footed winger able to play on both sides of the attack, Moreira is described as a fast, explosive and technically gifted footballer, most notably excelling in dribbling past his opponent.