The South American side created a number of gilt-edged chances, but Gonzalo Higuain, Lionel Messi and Rodrigo Palacio all failed to break the deadlock, thus allowing Mario Gotze to fire Germany to glory after 113 minutes of play.
And Lahm says his team held their nerve and were always sure they would see it through before the game had to be decided by penalties.
"The team stayed calm and patient, we knew that we had something left at the end," Lahm told reporters.
"It's unbelievable what we have achieved. We improved throughout the tournament and didn't get down when things didn't always go our way.
"We just stuck to our path and at the end we're standing here as world champions. It's an unbelievable feeling."
Lahm then went on to discuss Germany's lack of a true superstar and insisted that it's all about the team rather than about individual players.
"It doesn’t matter if you have the best individual players, as you need to have the best team unit."