Morata admits he's never seen anything like the Barcelona teen.
"He has a very determined character. That's hard to find in a person his age. He has a very clear idea of what he wants to do," the 32-year-old tells The Athletic.
"He has a lot of personality and has everything in front of him. Honestly, I've never seen anything like it. I have never seen such a player. One training session was enough to realize that he is different, that he is a phenomenon."
Morata is convinced that Yamal will become one of Spain's greatest players.
"Every 20 or 30 years, one or two appear like Cristiano (Ronaldo) and Messi. In my opinion, he has what it takes to make history. I am convinced that if he does not become the greatest player in the history of Spain, he will definitely become one of them.
"He already made history with us by winning the EC. He was 16 when the tournament started and I hope he continues with this because he is my teammate, because he can make me win more things with the national team and because my children want to meet him, get to know him, go and watch matches and all that."