It wasn’t until past the half-hour mark that the match saw the first notable effort on goal as Germany’s Melanie Leupolz fired in a powerful effort that caused Bryane Heaberlin some anxious moments, before the ball narrowly cleared the crossbar.
Then USA finally made some attacking headway as Maya Hayes made a driving run and shot from her position on the right side of the forward line.
It proved to be a portent of things to come as right fullback Crystal Dunn used her pace and power to cut in from the flank and pull the ball back for Kealia Ohai, who coolly swept home from near the penalty spot.
Full-back Leonie Maier hit a long-range effort with 15 minutes remaining which Heaberlin pushed onto the crossbar, as the champions became increasingly desperate.
Despite a succession of corners, Germany could not break the resilience of the Stars and Stripes.
Lina Magull had an excellent chance to draw Germany level with the last kick of the match, but Heaberlin remained cool to produce a crucial sprawling save.
“This victory is the reflection of many people’s effort,” said USA coach Steve Swanson. “We have a very together team. We faced some adversity in the group phase, and the players learnt from that. Our character showed up tonight.
“Since the quarter-final, we played against Korea DPR, Nigeria and Germany, three group winners. And we won, it says a lot about the quality of our team.”