Soccer crowd sings national anthem a cappella after audio system goes out (VIDEO)

Fans gathered at Sporting Park to watch the soccer match between Philadelphia Union and Sporting Kansas City Saturday night showed their patriotic spirit loud and clear before the game started. Loud being the key word.

While the pre-game national anthem was played, the public address system and microphone went out leaving everyone without musical accompaniment. So the fans took over. Instead of letting the song go unsung, the entire crowd cleared its collective throat and belted out a stirring a cappella version of "The Star Spangled Banner,"  providing its own volume to get the night started.

And everyone knew the words.

The Union —who hadn't won a game since August — were just as inspired and went on to a 1-0 victory.