Crushing modest Saudi Arabia 8-0 was pleasing but Ireland will be a different proposition, Germany coach Rudi Voeller said on Sunday.
"I'm satisfied with the victory and the good position we're in, but that's it," the former striker said, playing down the significance of Germany's biggest World Cup win in their opening group E match at the Sapporo Dome on Saturday.
"The only thing that matters is that we picked up three points against a team who will probably end the tournament with none," he said.
"Ireland are not in the same league as Saudi Arabia." Germany play Ireland on Wednesday in Ibaraki.
The 1990 World Cup champion said nobody in the Germany squad would get carried away by the Saudi rout.
"That will not happen after all we've been through over the last two years," said Voeller who took over as coach in the wake of Germany's disastrous first-round exit from Euro 2000.
After needing to beat Ukraine in the playoffs to qualify, the triple world champions entered the finals co-hosted by South Korea and Japan with lower expectations than usual.
Ireland's 1-1 draw with Cameroon on Saturday means they should survive their group if they win again on Wednesday. But beating Ireland, Voeller warned, is no formality.
"They put up a convincing show against Cameroon and they're not going to be overawed," he said.
Midfielder Bernd Schneider, who completed the 8-0 rout on Saturday with a superb free kick, shared his coach's analysis.
NOT THROUGH YET
"We are not in the round of 16 yet," he said. "Ireland and Cameroon will both challenge us much more than Saudi Arabia did. Ireland, in particular, are brave and tough physically. But we have no fear."
Liverpool's Dietmar Hamann, who knows most of the Irish players from the premier league, said the sending home of playmaker Roy Keane after a bust-up with coach Mick McCarthy could play in Germany's favour.
"The absence of such a vital player is bound to have some influence sooner or later," said Hamann, who was instrumental in a defensive role at the centre of midfield on Saturday.
"If we can remain as compact in defence and as aggressive in attack as we were yesterday, we'll be in the next round."
No longer the awe-inspiring force they once were, Germany cannot believe the glory days will return just because of one victory, no matter how spectacular.
But there is hope as elegant midfielder Michael Ballack, suffering from a bruised foot, appears to be recapturing his best form while striker Miroslav Klose lived up to expectations on his World Cup debut with his third hat-trick in 13 internationals.
"I was relatively quiet even before the game because I was happy with the training sessions, but it's true that I'll be sleeping better now," said Voeller.