The pair spent just over a month together before the Barca great was sacked as youth coach after disagreements with management.
Ilaix told Mundo Deportivo: "Valdés is a coach with a lot of character. Knowing how he is, with that character, he will be one of the great coaches in the world.
"In the short time I've been with him, you can know that with his personality he will achieve what he wants. I wish him good luck and hopefully one day we will meet again in the future."