Ronaldo joined Sporting's other youth players who trained at the Academia Sporting, the club's football academy, in Alcochete. He became the only player ever to play for Sporting's under-16, under-17, under-18, B-team, and the first team, all within one season. He scored two goals in his league debut on 7 October 2002, which Sporting CP won 3–0 against Moreirense, while featuring for Portugal in the 2002 European Under-17 Championship