Mick McCarthy says his Republic of Ireland team are ready to "kick the backside" of any opponents who underestimate them.
The Ireland boss was speaking ahead of Wednesday's Group E fixture in Ibaraki against a German side buoyed by their 8-0 demolition of woeful Saudi Arabia on Saturday.
But while McCarthy praised Germany's clinical finishing against the Saudis, he said he would be "disappointed" if his defence conceded similar goals.
"You have to look at what we've achieved and not worry about what the other team has done or may do," he said.
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Why should we be afraid after we have come though a group containing Holland and Portugal?
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Mick McCarthy
"Some of the lads will tell you that teams go to Highbury, Anfield, or Old Trafford and it is different.
"They might not be great teams but they are playing the club, they are playing the name, and I think that has worked in reverse for us at times because when we've turned up people look at us and think: 'We're only playing Ireland, not a big nation, they have not got a great history in world football.'
"Then they get their backsides kicked for taking us lightly.
"It's happened on a number of occasions, although I don't suspect that the German team will treat us lightly.
"I always believe it is our performance that counts, how we play.
"I respect the Germans, it was a great result against Saudi Arabia.
"I think that anybody who gets beaten 8-0 though must be fairly culpable and responsible defensively.
"I don't believe you can score eight great goals and there are no defensive errors. I've seen the goals and I'd be disappointed if we had conceded them, that's for sure."
Kevin Kilbane and Gary Kelly seem likely to get the Irish midfield flank roles with Jason McAteer still struggling because of a knee problem.
But despite the loss of McAteer, McCarthy insisted the famous resilience of the Irish would see them through.
"Why should we be afraid after we have come though a group containing Holland and Portugal, who are by all accounts stronger than Germany are at the moment?" he said.
"We will give them the respect they deserve but when the game kicks off that respect will go."