Thiago Alcantara has rebuffed the criticism aimed at David de Gea during the World Cup group stage.
De Gea spilled Cristiano Ronaldo's shot in Spain's dramatic 3-3 draw with Portugal to open Group B, and though he kept a clean sheet in the 1-0 victory over Iran, he conceded two of Morocco's three shots on target in a 2-2 draw on Monday.
Bayern Munich midfielder Thiago, who started just one of Spain's three group games, suggested the Manchester United shot stopper's hard work in training would go some way to silencing his critics.
"If you have seen the matches of David de Gea at Manchester United you can see that he is a porterazo [magnificent goalkeeper]," he told reporters.
"To criticise, you have to see everything, including how he works in training like an animal."
Thiago feels improvements were required all over the pitch ahead of Spain's clash with Russia in the round of 16, which takes place at Moscow's Luzhniki Stadium on Sunday.
He called for the Spanish media in Russia to get behind the team as they prepared for a partisan crowd in the capital.
"We are not going to play against eleven Russians, but against thousands of them," said Thiago. "We are all far from home and in theory supporting Spain.
"I agree that we have made mistakes in defence. I know we're not playing our best, but let's win - we're all together.
"What needs to be improved? Everything. But that starts with trust. You have to have your own trust and trust in your team-mates."