Low has admitted that his team need to be better as the competition reaches its critical stage.
"There's been lots of light, but also plenty of shadows, some good things, but also things which didn't work," Low told reporters.
"We won our group, which was our primary objective, so we are happy, but we are also self-critical and we know that we can play better.
"We've not reached our limit yet, and now the knockout phase begins, the decisive games are here."
Germany face Algeria in their last-16 clash on Monday.