Morata squandered a number of opportunities and was greeted with boos from the crowd as he was substituted in the second half.
But La Roja manager Luis Enrique maintains he was satisfied by the performance of the former Real Madrid forward.
"He has the personality to endure it and I would more like [him] to be applauded," Luis Enrique told a post-match media conference.
"Morata is a great player who does things well in attack and defence.
"I have heard the whistles for Morata but then he was applauded off. He does a lot for the team and he is used to these situations so I do not think it will affect him."
Barcelona midfielder Pedri, who became Spain’s youngest ever player at a major tournament at 17 years, added on Morata: "We can all fail, we all do. He [Morata] works a lot for the team and that can be seen on the field. He needs support. I tell people to keep trusting us, we are a great team.
"We created so many chances that I'm sure the goals are coming. I know there will now be good video analysis to see why it is we didn't score."
Spain will take on Poland in their next game on Saturday.
