Joachim Low's side were drawn in the 'group of death' alongside Portugal, Denmark and the Netherlands. However, while Flick admits that it will be a tough test, he remains confident that Die Mannschaft will reach the knockout rounds.
"It's important to win the first game," he said.
"We are sure that we will advance past the group stage. But we have to be there from the first moment.
"We expect Portugal to be on [our] level. Nani and Ronaldo are good for surprises."
The Germans kick off their campaign against Portugal this evening.