Felix, runner-up in Athens and Beijing to Jamaica’s Veronica Campbell-Brown, overcame a sluggish start to lead coming off the bend and was never going to be caught, the 26-year-old clocking a time of 21.88s to finish 0.21s ahead of 100m champion Shelly-Ann Fraser-Pryce.
America’s Carmelita Jeter, silver medallist over 100m, took bronze with Campbell-Brown fourth and failing in her bid to become the first woman to win a track event for three Olympics in succession.
The United States then enjoyed a one-two in the 110m hurdles as Aries Merritt stormed home to victory in 12.92s, the fastest time in the world this year and just 0.01s off the Olympic record set by Liu Xiang in Athens in 2004.
Team-mate Jason Richardson took silver in 13.04, with Jamaica’s Hansle Parchment taking bronze in a new national record of 13.12s.
Britain’s Lawrence Clarke was fourth in 13.39s, while defending champion and world record holder Dayron Robles of Cuba pulled up injured midway through the race.
On a truly memorable night for the USA they had more reason to celebrate when first Brittney Reese won gold in the women’s long jump while Misty May-Treanor and Kerri Walsh won gold in the all-American final of the women’s beach volleyball.
The duo claimed their third consecutive Olympic title after they defeated number six seeds Jennifer Kessy and April Ross in straight sets.
Meanwhile, Russia’s Natalya Antyukh won the 400m hurdles title, just holding off America’s Lashinda Demus.
Antyukh recorded a personal best time of 52.70s to finish just 0.06 outside the Olympic record held by 2008 champion Melaine Walker, with Demus setting a season’s best of 52.77.
Czech Zuzana Hejnova claimed the bronze medal just ahead of Jamaica’s Kaliese Spencer.
Elsewhere, Algerian Taoufik Makhloufi will not be the subject of an International Olympic Committee investigation into his 1,500 metres triumph which came the day after he pulled out of an 800m heat.
Makhloufi ran less than 150 metres of his 800m race on Monday morning before stopping.
He was initially disqualified from the Olympics for not providing what Games chiefs called “a bona fide effort” but then reinstated after being seen by a doctor, and he won the 1,500m gold last night by an impressive distance.
The 24-year-old’s victory was described as “surprising” by Steve Cram, Britain’s former 1,500m world record holder, but the IOC said the International Association of Athletics Federations (IAAF) were happy with what had taken place.
IOC spokesman Mark Adams said: “Obviously the IAAF is happy with the procedure that happened.”
Meanwhile, Great Britain’s Lisa Dobriskey and Laura Weightman qualified for the final of the women’s 1500m, but Hannah England missed out.
Dobriskey, 28, eased home in 4 minutes 5.35 seconds to ensure she was one of the five who qualified from the first semi-final.
Weightman, 21, qualified as one of the fastest losers to reach the final in her first ever Olympics.
England, who has struggled with injury this year, was ninth in her heat.