Ewerthon made an immediate impact on his Borussia Dortmund debut when he scored and set up a goal for Jan Koller, who in return set up a goal for him, as Borussia Dortmund won 2–1 against St. Pauli on 29 September 2001. In a follow–up match against Borussia Mönchengladbach, Ewerthon set up the club's first goal of the season before earning himself a scoresheet, in a 2–1 win over Borussia Mönchengladbach. Since joining the club, he quickly became a first team regular under the management of Matthias Sammer. Ewerthon then scored three goals in three matches between 17 November 2001 and 1 December 2001. Later in the 2001–02 season, his goals helped the club secure the Bundesliga title for the sixth time in their history. During the UEFA Cup campaign, Ewerthon scored two times in the knockout stage against Lille and Slovan Liberec. In the first leg semi-final of the UEFA Cup, Ewerthon set up two goals during the match, in a 4–0 win over AC Milan. Despite losing 3–1 in the second leg, they reached the UEFA Cup final and played in the UEFA Cup Final which Dortmund lost 3–2 to Feyenoord at their opponents' De Kuip ground in Rotterdam. After the match, German newspaper Kicker said about his performance: “Did not enter the game at all, offensively without effect, was replaced. The only sign of life: When he initiated the counterattack, which led to the penalty.” At the end of the 2001–02 season, Ewerthon went on to make thirty–four appearances and scoring twelve times in all competitions.