After 120 minutes of football could not split the teams, both of which had scored in the second half of regulation time, the match came down to penalties.
The hosts were clinical landing all four of their attempts, while the South Americans stuttered as Lehmann saved the efforts of Roberto Ayala and Esteban Cambiasso to start a nation wide party.
Two-time World Champions Argentina had been 10 minutes away from a trip to Dortmund for a semi final when they led 1-0, only for striker Miroslav Klose to score his first header for Germany in three years to level the scores.
The Polish born striker sent the ball into the back of the net after substitute midfielder Tim Borowski had flicked on a Michael Ballack free kick.
Germany’s Jens Lehmann
It had been the Germans who were forced to chase the game for the first time in the tournament when Argentine defender Roberto Ayala put his team ahead.
The Valencia defender lost his marker and got on the end of a Juan Roman Riquelme corner just three minutes after the break to score his seventh goal for his country.
In the 70th minute Jose Pekerman was forced to make a crucial substitution when goalkeeper Roberto Abbondanzieri succumbed to an injury he had picked up in a collision with Klose.
It put Atletico Madrid custodian Leonardo Franco between the sticks, but importantly left Pekerman with the inability to bring the likes of Lionel Messi or Pablo Aimar on in the dying stages.
He did have his chance two minutes later but opted to bring on defensive midfielder Cambiasso for Riquelme as he decided to attempt to hold on to the one goal advantage.
It proved a poor decision.
In the first half neither goalkeeper had much work to do with the four shots on goal the lowest of any half of football thus far at the World Cup.
And they’re off to the semis
Three of the four shots came from Germany and their best chance fell to captain Michael Ballack as his header flew over the bar after a delightful cross from Bernt Schneider.
Both sides were content with slow moving build up plays, but despite their best efforts the final pass was lacking.
Germany will now play the winner of Italy v Ukraine, but there will be plenty of partying throughout the country before then.