Julen Lopetegui hailed Isco's form that saw him score two goals as Spain beat Italy 3-0 in a World Cup qualifier on Saturday.
The Real Madrid midfielder has been excellent for his club in recent months, after finally beginning to show the potential he has struggled to fulfil, seemingly until now.
A former Valencia midfielder, Isco was signed by Real from Malaga in 2013 but he has only really begun to truly shine under current boss Zinedine Zidane.
A delighted Lopetegui said of his star: "Playing regularly, gaining important experience with his club and with us means that as a footballer he is growing.
“It is one thing to have quality and another to be a great player.
“Isco has always had quality and now he is becoming a great player.”
Alvaro Morata added a third goal for Spain, after coming off the bench, with Lopetegui adding that he is happy with his side's progression as they close in on World Cup qualification.
He said: "We are happy, not yet satisfied because we are not qualified but happy because the team responded very well against a difficult opponent.
"We are on the right track, but we have three more games to go.”