Sami Khedira lamented Germany's "unnecessary, stupid defeat" to England, with team-mate Mario Gomez conceding it a was "somewhat inexcusable" result.
The world champions were given a shock in Berlin on Saturday night as Roy Hodgson’s men rallied rather than wilted after failing two goals behind.
Toni Kroos' fine strike from distance was followed by a lovely Gomez header in the second half, but England returned fire through Harry Kane's impressive strike and an exceptional Jamie Vardy flick.
Eric Dier’s stoppage-time header completed a famous 3-2 win at the Olympiastadion, leaving the hosts shell-shocked.
“It was an unnecessary, stupid defeat,” Germany midfielder Khedira said.
“We all need to take a look at ourselves and work hard now.
“We did a lot right up until the second goal, then after that we were much worse — and England punished us.
“However, we played well for an hour. We need to play well for 90 minutes against Italy (in Tuesday’s friendly) and in the European Championship.”
Kroos believes Germany’s new defensive set-up played a part in their unravelling, but admitted “nevertheless it shouldn’t be allowed to happen”.
Fellow goalscorer Gomez was equally frustrated after seeing his hopes of winning the grudge match extinguished.
“It is somewhat inexcusable,” the Germany striker said of the loss.
“We were playing very well until we were 2-0 up but we didn’t use enough of our chances.
“Afterwards, we stood off our opponents too much and England are very strong from set-pieces.”
Meanwhile Jack Butland is to undergo a scan on Sunday on the ankle injury he sustained during the first-half of the friendly win.
The English goalkeeper was carried off on a stretcher and replaced by Fraser Forster.
The 23-year-old took to social media on Sunday to confirm he is to have tests to determine the extent of the problem, tweeting: “Thank you for all your messages, I’ll be having a scan today to see the damage to my ankle and will work hard to get back fit! thank you!”
The former Birmingham custodian was hurt moments before Kroos opened the scoring in the 43rd minute.
Butland had the chance to put the ball into touch to receive treatment, but chose instead to punt it down field, whereby Germany claimed possession and raced forward through Real Madrid midfielder Kroos, who beat Butland with a low 25-yard shot at his near post.
Butland added on Twitter: “Firstly, what a night to be involved in! an incredible and much deserved win against the World Cup winners, makes me proud to be English!
“But my nature to not give up was my downfall, the injury I’ll recover from but more importantly the experience I’ll learn from!”
