BUENOS AIRES, Feb. 18 (Xinhua) -- Real Madrid-bound teenager Vinicius Junior came off the bench to score as Flamengo won Brazil's Guanabara Cup with a 2-0 victory over Boavista on Sunday.

Flamengo took the lead just after the hour mark at Estadio Kleber Andrade in Cariacica when defender Fernandes turned the ball into his own net.

Vinicius left his mark on the match just minutes after replacing Lucas Paqueta. The 17-year-old made just enough contact with Everton Ribeiro's lofted pass to beat Boavista goalkeeper Rafael and guarantee his first title with the Rio de Janeiro club.

The result hands Flamengo an automatic berth in the semifinal of the Carioca championship.

Vinicius became the most expensive teenage footballer ever last May when Real Madrid agreed to sign him for 45 million euros.

The move was originally slated to take place next July, but Flamengo are reportedly negotiating with the reigning Spanish champions to keep him for another year.