In an action-packed night on the track, Matt Centrowitz held off the closely clustered field in the final straightaway to become the first American man to win the 1,500 meters since 1908.
And it was another record-setting night for Allyson Felix. She anchored the U.S. to victory in the 4x400 relay victory, giving her a sixth career gold medal, the most ever by a woman in track. She broke her own record, which she set on Friday night as part of the gold-medal winning women's 4x100-meter relay.
The only American woman to win more gold medals than Felix in any sport is swimmer Jenny Thompson, who has eight.
Also, Britain's Mo Farah won the 5,000 meters to go with his 10,000-meter title earlier in the games, repeating a difficult double victory in distance running that he also pulled off in London four years ago.
Farah spends much of his time in the U.S. and often trains with Centrowitz.
In 2012, Centrowitz missed a medal in the 1,500 by four-hundredths of a second and he made it his mission to improve his speed on the last lap. It showed on Saturday.
The entire pack ran a pedestrian pace for the first three laps and was tightly clustered, but then Centrowitz burst into the lead and unleashed a blistering 50.6-second last lap that no one else could match. His time was 3:50:00.
His father, also named Matt Centrowitz, cheered wildly in the stands. The elder Centrowitz was an Olympian himself as a distance runner, though he never medaled. He's now the track coach at American University in Washington.
While the U.S. has won far more track medals than any other country in Olympic history, the 1,500 meters — the metric mile — had eluded the Americans ever since Mel Sheppard took the event in 1908 in London.
Winning two distance events has become increasingly rare at the Olympics, yet Britain's Farah has pulled it off in London and in Rio. He has relied on the same strategy time and again, hanging back for the first half of the race, then gradually moving through the pack, and ultimately sprinting the the final lap at a pace his rivals cannot sustain.
In other gold medal events, the U.S. won the men's 4x400-meter relay. Like the women, the American men also held off Jamaica, their main competitor in sprints.