De Gea's mistake would prove costly as Spain and Portugal ended up sharing the spoils in a 3-3 draw, and while the 27-year-old was happy with the support within the Roja camp, he was critical of the situation outside it.
"I like that there are criticisms," De Gea is quoted by The Independent as saying. "Diego Costa has also been criticised and he scored two goals. I haven't killed anyone, either. I'm happy with the national team... I don't see much that they support me from Spain.
"My own criticism is bad enough. I would have liked that they defended me more in a difficult moment in my life, with an issue from outside the game. I am happy with the support from the manager and the lads.
"This can happen. It's a mistake. We put on our gloves and go out into the field and we know how difficult it is. I count on the support of the coach and my colleagues to continue. I will stay calm. It was a difficult ball, I'll keep training and try to do things right. I haven't killed anyone."
De Gea has won 30 caps for Spain, keeping 15 clean sheets.