He told Cadena COPE: "It was normal the first season, because he is a very young player. He needed a bit of adaptation because Barça is a great club and it is not easy to play well when you're in the first season. I have a lot of hope for him in the second, after the World Cup victory.
"It was very decisive and I saw a very collective Dembélé. He always has the ability to unbalance his rivals and produced a magnificent football.
"I think Barça would be wrong if they sell him. Ousmane is for the present but above all for the future. I said last year that they needed a little patience with him, but now he knows the language, the club and his teammates. I hope it's a good season for him."