Cristiano Ronaldo packs a powerful strike from dead-ball situations and the Germans have been told to minimise the risk of commiting fouls outside the box in one-on-one situations.
"I think just steel helmets and to make themselves big," Flick told reporters on Friday when asked how the Germans planned to deal with any potential free kicks from the Portuguese forward.
"At 20, 25 or even 30 metres we need to be clever in the one-on-one situations. Ronaldo has an exceptional free kick quality."
Germany also play Netherlands and Denmark in their group.
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