Spain's under-pressure goalkeeper David de Gea has the backing of coach Fernando Hierro, who said he will stick by him for his side's next game against Iran on Wednesday despite his performance in the 3-3 draw with Portugal.

The Manchester United keeper let a tame shot from Cristiano Ronaldo through his arms for Portugal's second goal on Friday and has been criticised in Spain for his badly positioned defensive wall when Ronaldo struck the late equaliser.

"We have our full confidence in him, I know very clearly from experience that footballers need to feel the confidence, not just in the good times," Spain's interim coach Hierro told reporters on Monday at the team's base in Krasnodar.

De Gea has repeatedly got his club out of jail and was voted player of the year at United last season. But he has made costly errors in three of his last four outings for Spain, also letting in cheap goals against Switzerland and Argentina.

"He's had difficult moments but you can get over everything with time. Goalkeepers have a special psychology, and sometimes action-reaction is not enough. De Gea needs time and oxygen," added Hierro.

"All players need confidence and I'm going to give that to them. De Gea has taken everything naturally, we have to get used to debate because it's part of the job. No-one has given him anything for free, and we need to be fair with him."

Midfielder Isco also gave his backing to Spain's number one, who for now is fending off competition from Athletic Bilbao's Kepa Arrizabalaga and veteran keeper Pepe Reina.

"De Gea is one of the best in the world, he knows how to react, and we are showing him a lot of love," Isco said.

"We have to help him because he helps us a lot, and that's what this group is all about."

A former Spain defender and until last week the Spanish football federation's director of football, Hierro has been catapulted into the unexpected position of head coach after Julen Lopetegui was sensationally sacked last Wednesday for negotiating a move to Real Madrid on the eve of the tournament.

"I came here in a suit and I’m going to return in a tracksuit," added Hierro.

"I was the sporting director but things are how they are, and in football things like this happen. Due to these circumstances, I have a fantastic challenge, a challenge I’m working on all day every day."