Oliver Bierhoff knows Germany only have themselves to blame after they crashed out of a second successive World Cup at the group stage on Thursday.
Hansi Flick's side beat Costa Rica 4-2 in their final Group E match at Al Bayt Stadium, but that was not enough to see them through to the round of 16.
Japan's surprise 2-1 win over Spain ensured the Samurai Blue finished top and Luis Enrique's side secured second place due to having a superior goal difference to Germany.
Having failed to advance from their group in Russia four years ago, Germany were left stunned after falling short once again in Qatar.
A shock 2-1 loss to Japan in their opening match cost Germany, who held Spain to a 1-1 draw before claiming a first victory of the tournament in what proved to be their final game.
Bierhoff, Germany's national team managing director, said: "We're extremely disappointed. We're angry too because we had things in our own hands in all three games.
"Ultimately, football is a simple game. You have to score lots of goals and concede as few goals as you can, which we didn't manage to do.
"We could have put more pressure on Spain tonight if we had taken our chances and scored more goals. A trend of the last few years has been us throwing away games we’ve controlled."
Japan will face Croatia for a place in the quarter-final next Monday, with Spain taking on Morocco 24 hours later.