Kelvin Mateus de Oliveira (born 1 June 1993), known simply as Kelvin, is a Brazilian professional footballer who plays as a right winger for FC Ryukyu in J2 League. He played for five of the Campeonato Brasileiro Série A's Big Twelve, as well as three other clubs in Série B. Abroad, he represented Porto, where he contributed to a Primeira Liga title in 2013. Club career Early years and Porto Born in Curitiba, Paraná, Kelvin spent two seasons with local Paraná Clube in the Série B. In late June 2011, aged only 18, he signed with FC Porto in Portugal. Together with teammate Christian Atsu, Kelvin was sent on loan to fellow Primeira Liga club Rio Ave F.C. for the 2011–12 campaign. He made his debut in the competition on 21 August 2011, in a 1–0 away loss to Académica de Coimbra. Kelvin returned to Porto for 2012–13, spending most of the season with the reserves in the Segunda Liga. He managed to score, however, three important goals for the first team as a substitute, helping to home wins against S.C. Braga (3–1) and S.L. Benfica (2–1), the latter coming in the 92nd minute. Loans On 13 January 2015, Kelvin joined Sociedade Esportiva Palmeiras on a loan deal. He played five games as they won the Copa do Brasil that year, and scored in a 5–1 home victory (6–2 aggregate) in the second leg of the second round against Sampaio Corrêa Futebol Clube on 12 May. Kelvin moved to São Paulo FC, also on loan, on 2 February 2016. On 6 April, he recorded the first continental goal of his career, in a 6–0 home thrashing of Venezuela's Trujillanos F.C. in the group stage of the Copa Libertadores. He scored once in the national league on 11 September, opening a 3–1 defeat of Figueirense FC. On 3 February 2017, Kelvin was loaned to CR Vasco da Gama. Limited by injury in his first year in Rio de Janeiro, he nonetheless had his link extended the following January; he scored once on 5 May 2018 to conclude a 4–1 win over América Futebol Clube after coming on as a substitute. Later career In late April 2019, free agent Kelvin signed with Fluminense FC until the end of the season. He left three months later having played for only two minutes, agreeing to a contract at Coritiba Foot Ball Club. In nine