In the past, it's been called Germany's most dangerous weapon - and on the evidence of yesterday's duel in the sun in Montpellier, it's still as potent as ever.
Mental strength, the ability to grind opponents down in the most improbable situations, took them into the last eight in the World Cup, a modest achievement when set in the context of their enviable record and yet sufficiently welcome to entice Berti Vogts into something approaching a smile at the finish.
"Phantom Deutschland" ran the headline in one of the German daily papers in a foreword to the game and the plot which ensued proved that it was not inapt. On the evidence of their last three games, they are certainly not good enough to win the trophy. And yet those who go against them risk being proved wrong.
Undermined by some crass goalkeeping errors by Andreas Kopke in the first instance, they have revealed little of the defensive stability which once was another stock-in-trade and significantly, the two centre backs who started out in this competition, Jurgen Kohler and Olaf Thon, were both on the bench yesterday.
Kopke's performances have been nightmarish in the extreme and while he twice saved them in perilous situations, Vogts, one suspects, must soon make one of the more difficult decisions of his managerial career and look elsewhere for the assurance which Kopke, a veteran of 57 international appearances, has so far failed to provide.
Even Lothar Matthaus, the most experienced World Cup campaigner of them all, occasionally betrayed the signs of panic as he watched his goalkeeper spill ball in a manner which invited retribution with such a skilled predator as Luis Hernandez lurking in and around the six-yard area.
That was the downside of Germany's display. The more encouraging aspect was the manner in which Oliver Bierhoff crashed home the winner after missing a dolly chance at a stage when the game was still scoreless approaching half time.
Bierhoff, no less than some of his distinguished teammates, has scarcely looked comfortable in any of his games here, but his headed goal, the best of its kind since the start of the championship finals, was a thing to set the imagination racing.
Minutes earlier he had just fractionally mis-timed a similar effort, but there was to be no second reprieve for the flamboyant Mexican goalkeeper, Jorge Campos, beaten at his left-hand post by the sheer pace and weight of the header.
Jurgen Klinsmann had earlier extracted the maximum retribution for Raul Lara's mistake and in that there was a sense of poetic justice after Raul had taunted German supporters when Hernandez gave them their shock lead.
"German teams are never beaten until the final whistle - it was our spirit which saved us," said Klinsmann. And a voice from the back went - "I'll drink to that".
