Jan Oblak
Jan OblakReuters

Real Madrid's hopes of signing Benfica goalkeeper Jan Oblak have been dented after reports in Portugal claim city rivals Atletico Madrid have reached an agreement to sign the Slovenian.

The 21-year-old -- who joined Benfica from Olimpija Ljubljana in 2010 -- is among a group of talented young stoppers to emerge from European in recent years. He started last season's campaign on the bench, but earned his place in Jorge Jesus's starting line-up and has since attracted interest from big European clubs such as Juventus.

Earlier this month it was reported that Los Blancos had held talks with Oblak's agent aimed at securing his services ahead of the next campaign as a successor to Iker Casillas when the Spain and Real captain's contract ends in three years.

Oblak -- who has four years left on his deal at Estadio da Luz and a €20m release clause -- is one of the first names on Los Blancos' wishlist. His youth and potential would make him an ideal long-term signing.

However, according to Portuguese daily newspaper A Bola, Atletico and Benfica have agreed to the transfer of the Slovenian stopper for €20m – and the contract could be signed in the next 48 hours.

Los Rojiblancos want him for this summer with Thibaut Courtois expected to return to Chelsea next season, especially since Blues boss Jose Mourinho has gone on record saying: "when the World Cup is over, Courtois will come straight back to London".

For any deal to go through, however, Atletico would need money from the sale of French midfielder Josuha Guilavogui – who has failed to claim a place in Diego Simeone's starting line-up – to the Portuguese side next season.

Last month, Oblak's agent Miha Mlakar already confirmed that both Real Madrid and Atletico were interested in his client. He insisted that Los Blancos were the first to approach him though.