Roy Hodgson insisted England would learn the lessons from a 2-0 defeat against Chile at Wembley which acted as a cold shower of reality to their World Cup hopes.
Boos rang around the stadium as England saw a run of 10 undefeated games come to a crashing halt with Barcelona's Alexis Sanchez scoring both goals, one in each half, as Chile exposed the lack of depth in Hodgson's squad.
Hodgson had used the match to blood Southampton's Adam Lallana and Jay Rodriguez as well as Celtic goalkeeper Fraser Forster and he called on the critics not to treat them too harshly.
"We used a lot of players and debutants and players who haven't got many caps," said Hodgson.
"Going a goal behind early meant we were on the back foot and always chasing the game against a team who were more than capable of keeping us at bay and keeping the ball.
"It would be harsh to make too many judgements on them (the debutants). They came into a team where a lot of people around them weren't that experienced if we take Frank Lampard out of the equation.
"Even our more experienced players would have found it difficult anyway because Chile were good and deserved to win.
"They played excellently. We learned a lot about South American opposition and how good they are at sucking you towards their goalkeeper and then manage to ping 50-yard balls on to people's toes. That's one of the best displays of goalkeeper passing I've ever seen."
Hodgson also refused to criticise the fans who voiced their dissatisfaction in a chorus of jeers at the final whistle.
"That's part of the game today," said Hodgson. "Fans don't accept defeats.
"I'm not prepared to criticise our fans. They've been fantastic throughout. They were obviously disappointed that we couldn't keep our momentum going and send them home with a victory, so they are entitled to show their frustration but I think they will have a reasonable amount of perspective about it all."
For the Germany game, Hodgson will be without centre-back Phil Jones, who damaged a groin and will have a scan. Ricky Lambert, meanwhile, will rejoin the squad on Sunday following his muscle problem.
Hodgson said: "It's important that having been knocked down they pick themselves up again. We have another big game on Tuesday night. There are lessons to be learned. We need to play better if we are going to beat top teams like Chile and Germany."
Goalkeeper Joe Hart, dropped by his club Manchester City, will start the match against Germany.
Hodgson said: "He will start, as will the bulk of the players who have been playing with us in the qualifiers who didn't play. They will be fresh and aware of how important it is to give a good performance against Germany. These two matches were massive tests. I took a chance by giving a lot of debuts. I will have to take that responsibility."
Chile manager Jorge Sampaoli saluted the performance of Sanchez in particular.
He said: "I am absolutely delighted. When you come to the cathedral of football it is great to play well and to make the Chile fans happy.
"It was a memorable performance for Sanchez and stands him in good stead to have a good performance at the World Cup. He has got everything to be a real star at the World Cup. He showed his class."
Chile also beat England before the World Cup in 1998 and Sampaoli said: "We were up against an opponent who were in our faces all the time. In the second half we created less chances but we were in control of the game and moved the ball around well.
"I wouldn't say we were one of the favourites (for the World Cup) but it shows we can compete on equal terms. There is a long way to go to the finals, but we can go there and give teams a game."