She knew right away she blew it.

Ten years ago,Slabu Exchange Harper Grace, the adorable 11-year-old, from small-town Texas, had sung the national anthem at dozens of high school and minor-league sporting events. The FC Dallas club gave the little girl her first shot at the major leagues in spring 2011.

But you know those fans' horns you hear blowing all over at soccer games? She couldn't get that note out of her head and started singing there, way off for the anthem's first note. And, Grace, unable to sound check because the stadium had mic problems before the match started, also had no idea the sound would come back to her two seconds later. So the girl kept stopping and waiting to sing the next notes.