Joachim Low was aggravated by Germany's performance on Saturday but admitted England played well enough to deserve a 3-2 win.
Toni Kroos and Mario Gomez had given the hosts the lead in Berlin before Harry Kane got a goal back and Jamie Vardy's spectacular strike brought England level and Eric Dier completed the comeback in stoppage time.
Low said Germany's second-half performance left him frustrated but also credited England.
"All in all I can say it is absolutely annoying for a coach to see you team squander a 2-0 lead," he said.
"I think, having lost this game it is not entirely undeserved, even when we were 2-0 up we weren't as in control as I would like us to be, we had problems in our structure and didn't create too many chances -- so England in a way deserved to win.
"If you ask me for conclusions to be drawn from this game there are some. This was a friendly match and they are all about showing us areas that need improvement and to be worked on."
Sami Khedira, who was captaining Germany in Bastian Schweinsteiger's injury-induced absence, agreed.
"We did lots right until 2-0, then England punished us," he said. "We lost our order. We played a good game for 60 minutes, we'll have to do that for 90 minutes at the European Championship."
Kroos was reluctant to write off the loss as a meaningless friendly.
"Of course the result is important, otherwise we could all just stay at home," Kroos said. "We played very well in the first half, then we defended badly. We left way too much room and didn't hold our ground."