Quincy Hall came from behind to win the men's 400m final for his very first Olympic gold medal.
It's the United States' first gold in the event since LaShawn Merritt in 2004 - USA swept the medals that year.
It's the first medal for the United States since Merritt earned bronze in 2016.
Hall finished the race in 43.40 seconds, a personal best - he was 0.37 seconds off world-record time.
It's the fourth individual gold medal for the United States in track and field, joining Noah Lyles (100M), Cole Hocker (1500M), and Ryan Crouser (shot put).
The 26-year-old finished in third in the world championships last year, but was a part of the gold-medal winning 4x400m relay team at the event.
