Germany coach Joachim Low has voiced his concerns with his side's defensive showing in Sunday's 3-1 friendly defeat at the hands of Slovakia.
Mario Gomez handed the world champions an early lead from the penalty spot after 13 minutes.
However, goals from Marek Hamsik, Michal Duris and Juraj Kucka ensured victory for Slovakia as Germany failed to keep a clean sheet for the eighth consecutive game.
Low saw reasons for optimism in possession, but was not impressed with Germany's performance at the back.
"I am pleased with our attacking performance. We had a few nice attacks and our movement was quite good," Low said at a news conference.
"But I have to be honest and admit we had problems defensively.
"It might have had something to do with the presence of both Mario Gotze and Julian Draxler, who are both number 10s. That's why Slovakia got too much space."
Low handed a number of youngsters the chance to earn a spot in Germany's final squad for Euro 2016, with Julian Brandt, Joshua Kimmich, Julian Weigl and Bernd Leno all winning their first caps.
"We cannot expect too much from the younger players in a game like this," he added.
"But Julian Brandt, Joshua Kimmich, Julian Weigl and Bernd Leno all have a lot of quality and have a bright future ahead of them."
Germany still have a number of injury worries ahead of the tournament in France and Low is keen to get some more insight on the availability of his three doubtful players.
"The most important thing for us is that everybody is healthy," he continued.
"We have a meeting scheduled with the medical staff to see how long Bastian Schweinsteiger, Mats Hummels and Marco Reus will still be unavailable for."