Morata has been forced to play second fiddle to Karim Benzema at Madrid this season, but he has scored nine times in his seven appearances for his country's youth team.
"These are football cases. With the national team I was also had such a role at the European Under-21 Championships and I finished as top scorer. I am calm. The national team helps me to become even more confident and to compete at my club," Morata told reporters at a press conference.
"Am I in a freer role with Spain compared to Madrid? It is not that, but maybe I have been so eager to prove myself with my club that I have sometimes played tricks on myself, that I have not done everything that I have needed to do.
"Gradually I am becoming calmer, with the Under-21s I have fun and I can also develop."
Morata is highly regarded at the Santiago Bernabeu.