Joao Felix is being backed to fulfil his potential.
Currently on-loan with Chelsea, Felix's future with parent club Atletico Madrid is clouded.
Estoril coach Ricardo Soares told Mundo Deportivo: "Joao Félix has a natural talent. He is an excellent player and I think that in the future he can be one of the best players in the world.
"In Spain he played some good games, but he has much more growth and he will surely show it in the future, because we are talking about a player with incredible talent, he is fantastic.
"Perhaps at first the adaptation was not as fast at Atlético as everyone expected, but we must not forget that there was a great economic agreement, and there is a great weight in the figures that were paid for it. But in the future he will show that those millions were well delivered because he has a lot of quality."