Spain defender Aymeric Laporte backed Alvaro Morata to "shut everyone's mouth" after the striker was jeered by his own fans during Monday's goalless draw with Sweden.
Morata missed a good chance in the first half and was then whistled by the Spanish supporters in Seville when he was substituted with 25 minutes left.
Luis Enrique picked Morata ahead of Villarreal's Gerard Moreno, despite Moreno scoring 23 goals in La Liga last season, second only to Lionel Messi.
"There are no doubts about a striker like Morata," said Laporte afterwards. "We know what he can do, it didn't go in for him today it's true, but in the next game he can score three and shut everyone's mouth. Let's hope so, we have to win the next match."
The stalemate means a disappointing start for Spain, who will be feeling the pressure ahead of Saturday's game against Poland, who earlier lost 2-1 to Slovakia in Group E.
"If we play 10 games like this, we win nine," said Laporte. "But this one hasn't gone for us. We missed chances today but maybe one day we score five, another none.
"We are not worried, we know that we have great players up there to score goals, just today it was not possible."