Isco was one of the key performers in La Roja's 5-0 win against Costa Rica on Saturday evening before leaving the field with a minor injury in the second half.
The 25-year-old was heavily used in club side Real's famous double-winning campaign last time out, playing 36 La Liga and Champions League matches in all, and he has impressed so far this term with four goals and three assists in the Spanish top flight.
"Isco is a player that is already settled in football's elite," he told reporters. "I say he's settled because he's really constant at a maximum level and that's really hard to achieve.
"He made it thanks to his enormous quality but, not only that, also thanks to his great state of mind that made him a great player. That's why he's settled at that level. As he said yesterday at the press conference, the best of Isco is yet to come, I have no doubt about it. He has the ambition, the attitude, the quality and the mentality for that."
Talk of a Premier League switch for Isco refuses to go away, meanwhile, as Manchester City are reportedly confident of landing him next summer.