Born and raised in Brazil, Anderson Luís de Souza, known as Deco, was scouted and bought by Benfica in 1997 from Brazilian club CSA. He received Portuguese citizenship in 2002 having completed five years of Portuguese residence, and subsequently opted to play internationally for the Portugal national football team.

Touted as a possible future successor for Rui Costa, his early release from Benfica and subsequent success with Porto, was considered as a "historical mistake' by the Lisbon club.
Under the guidance of José Mourinho at Porto, Deco was given the role of leading an ambitious, well balanced team. A key figure in the 2002–03 season, he scored 10 goals in 30 games was one of the key players in Porto's UEFA Cup final 3–2 win over Celtic.

The following season Deco helped a now well oiled Porto side recapture the national title and led the team to the Champions League Final, in which they thrashed Monaco 3-0, Deco scoring the second goal of the match. He was the Champions League's top assist provider and also suffered the most fouls as opponents attempted to stop Deco controlling matches.
That season, Deco won the UEFA Club Footballer of the Year and a move to Barcelona followed soon after.