On 24 August 2009, Vinh officially signed with Leixões and was given the number 29 shirt. Two days later, in a friendly match against Padroense F.C., he scored his first goal for the club, as a substitute, in the 89th minute to secure a 2–0 win. He was included in the 18-man squad for the match against defending champions F.C. Porto on 12 September, but did not make the field in an eventual 1–4 loss. His first-team debut came on 4 October, in a league contest against União de Leiria, making him the first ever Vietnamese footballer to play in a professional European league; he played the entire ninety minutes in an eventual 3–2 home win, despite trailing for most of the game.