Sami Khedira is at a loss to explain why top sides often struggle in their second matches at tournaments, but insists Germany are ready for the threat of Ghana.
Italy beat England 2-1 in their opening game but then lost 1-0 to Costa Rica while Brazil drew 0-0 with Mexico after winning the World Cup opener against Croatia, and even Netherlands struggled past Australia 3-2 after thrashing holders Spain 5-1.
Die Nationalmannschaft lost their second matches at Euro 2008 and the 2010 World Cup, and despite thumping Portugal 4-0 in their Group opener in Brazil, the Real Madrid midfielder says Joachim Low's side will have to be "tactically clever" against the Black Stars on Saturday.
"I can't explain why the second match is always hard after a win. I think it's a mental thing," Khedira told a pregame news conference on Friday. "We went through the same experience in 2008 and 2010. We don't want to come to the last game and worry.
"We will be totally focused against Ghana. It's an African team and they are very athletic. So we have to concentrate. And I think we will prevail. We have to be tactically clever," the Real Madrid defensive midfielder said.
Germany beat Australia in the first game of the 2010 World Cup in South Africa before losing to Serbia, but a narrow win against Ghana saw them through -- and Khedira expects another tough battle.
"We beat them four years ago, but it was a difficult match and we needed some luck," he continued.
"Ghana has excellent players who play in good clubs. They don't give up, they are robust and they are technically good."
National coach Low, meanwhile, described the pattern as "a psychological problem" for teams after a positive opening to a competition, but believes his side can prosper on the counter-attack.
"You can't have any lapses. If there's a lapse, you will lose," he said. "Their situation is that it's a final for [Ghana].
"They will fight until they bleed. They can attack very well; they are quick, ready to march on for 90 minutes. We have to defend well and be ready to attack with lightning speed once we win the ball."