Over the course of four finals at Olympic Stadium, American athletes claimed seven of the 12 medals awarded -- three gold ones, two of silver and two more of bronze.
Felix was joined as an American Olympic champion by long jumper Brittney Reese and 110-meter hurdler Aries Merritt. The United States came close to a fourth gold medal when Lashinda Demus just missed catching Russian Natalya Antyukh at the line in the 400-meter hurdles.
Americans also were running 1-2 in the decathlon after the first day of competition with Ashton Eaton out front of Trey Hardee.
Perhaps no one during these Olympics has defeated a deeper field than did Felix, who faced Olympic and world champions throughout the finalists in the 200-meter dash.
Twice Felix had finished as the runner-up at the Olympics and the woman who defeated her both times, Veronica Campbell-Brown of Jamaica, was on hand again to try to make it three in a row.
Shelly-Ann Fraser-Pryce and American Carmelita Jeter, who finished 1-2 in the 100-meter dash earlier in these Olympics, were also lined up for the 200 final. And so was Sanya Richards-Ross, the 400-meter gold medalist in London.
Felix won the world championship over 200 meters in both 2007 and 2009, but the lack of an Olympic title had left a hole in her career accomplishments.
All of that came to an end, however, when she powered around the turn with the lead and motored down the straightaway to defeat Fraser-Pryce in the time of 21.88. Jeter finished third to earn her second medal of the Olympics.
Merritt, who has dominated the 110-meter hurdles on the world track circuit this year, broke 13 seconds for his fifth consecutive race. His time of 12.94 easily got the best of fellow-American Jason Richardson. Jamaica's Hansle Parchment took the bronze medal.
Reese fouled on four of her six attempts in the long jump, but one of her two good ones was the best of all. She traveled 23 feet, 4 1/2 inches in the air to edge Russian Elena Sokolova for the gold medal.
Janay DeLoach of the United States moved into third position with her next-to-last jump and won the bronze over Ineta Radevica of Latvia by less than an inch.
In the women's 400-meter hurdles, Antyukh stumbled over the closing barrier and Demus came rushing from behind. Demus looked as if she would catch Antyukh at the line, but the Russian put on a final burst over her last three strides to win by 0.07 of a second.
Eaton, runner-up at last year's world championships, finished the first day of the decathlon with 4,661 points -- a massive 220 in front of Hardee. Damian Warner of Canada was in third place, trailing Hardee by 65 points.
The finals were set in the men's 200-meter dash, where Jamaica's Usain Bolt will attempt to win the event for the second straight Olympics -- just as he did in the 100-meter event. He coasted to a time of 20.18 to win his semifinal heat.