Guti was speaking about the claims of Spain coach Luis de la Fuente that Yamal can reach the heights of Diego Maradona, Lionel Messi and Cristiano Ronaldo.
He told AS: "Wow. I see him as a fantastic player and a potential Ballon d'Or winner, but you're talking about three players who are the best in the world.
"Maradona won the World Cup in Mexico without having a great team, and Messi and Cristiano won by scoring 50 goals over ten years. That's going to be very difficult for just anyone to achieve. I see Kylian as closer to achieving it than Lamine."
On Yamal's antics off the pitch, Guti insists he should be allowed to enjoy himself.
He explained, "It's the world we live in; there are so many social media platforms. So many people have phones and can report you in an instant. Everyone's talking and giving their opinion.
"He's a young guy who plays football really well. When it's his private life, he does what he wants. Nobody should interfere. We have to respect that."