Under the guidance of manager José Mourinho, Deco was given the role of leading an ambitious Porto team. A key figure in the 2002–03 season, he scored 10 goals in 30 matches and received 17 yellow cards and 1 red card. Deco was one of the key players in Porto's UEFA Cup final 3–2 win over Celtic that year. In the 2003–04 season, Deco helped Porto recapture the national title and led the team to the 2004 UEFA Champions League Final, in which Porto won 3–0 over Monaco, scoring the second goal of the match. He was the UEFA Champions League's top assist provider and also suffered the most fouls in the Champions League that season. That season, Deco also won the UEFA Club Footballer of the Year as well as the award for the best midfielder in the competition.