The outstanding contribution came from the fleet, long-legged Bambi of the track, Felix, who at the age of 26 finally has an Olympic 200 metres gold medal after being beaten into silver at the two previous Games by Jamaica's Veronica Campbell-Brown, who finished one place off the podium here in 22.38 sec.

In finishing ahead of the woman who had retained her Olympic 100m title earlier in the week, Shelly-Ann Fraser-Fryce, Felix, who clocked 21.88, also reclaimed for the US one of the four sprint titles which were annexed by Jamaican men and women at the last Olympics.

After her second, bitter defeat to Campbell-Brown in Beijing, a despairing Felix said she would have swapped all her world golds for an Olympic title.

Allyson Felix of United States crosses the finish line to finally win the Olympic 200m title

Now she finally has that desired object to set alongside the three golds and a bronze she has won at the distance at the last four World Championships.

"In Beijing I said I would give all those World Championship medals for the gold," said Felix, still wearing the wide and dazzling smile that had appeared on her face shortly after she floated over the finish line.

"Now I say I embrace all of the journey because it has pushed me all these years.

"And now it is a very sweet success."

Felix, who believed one of the key factors in her victory was the newfound aggression she had managed to carry over from competing here in the 100m, added: "For years those two defeats have been fresh in my mind.

"This has been a long, long time coming."

Fraser-Pryce was delighted with silver in a personal best of 22.09; Felix's teammate Carmelita Jeter, the world 100m champion, took bronze in 22.14.

With the score currently standing at 2-1 to Jamaica, however, the US chances of equalising in the men's 200m look less than healthy following tonight's emphatic semi-final victories by Jamaica's 100m gold and silver medallists, Usain Bolt and Yohan Blake.

Aries Merritt crosses the finishing line of the men's 110m hurdles with a personal best of 12.92sec

Before these Games got underway there was high expectation over the men's 110m hurdles final, where Merritt, with the four fastest timings of the season, was due to take on a field which included the 2004 and 2008 Olympic champions, respectively Liu Xiang and Dayron Robles.

A return of the Achilles tendon problem which undermined his hopes of challenging in the home Games in Beijing put paid to Liu's chances at the very first hurdle of his heat, however, and in the final Merritt's eventual victory came after Robles juddered to a halt with an obvious hamstring problem after hurdle five.

The Cuban, with Merritt and fellow American Jason Richardson, the world champion, either side of him, had already faded back into minor medal contention by then, however.

Merritt held his nerve and form to win in 12.92, the best time of 2012, and become the first US hurdler to win this title since Allen Johnson in 1996, with Richardson taking silver in 13.04.

Bronze went to Jamaica's Hansle Parchment, who clocked a national record of 13.12 to finish just one place ahead of Britain's 22-year-old Commonwealth bronze medallist Lawrence Clarke, who raised his game to earn a terrific result, finishing a hundredth of a second ahead of the 2009 world champion, Ryan Brathwaite of Barbados, in 13.39.

"I can't believe I came fourth in the Olympic Games," said Clarke, whose teammate Andy Turner, the world bronze medallist, failed to qualify from the semi-final after what has been an injury-ridden season.

"I didn't even expect to make the final."

Robles eventually clocked a time of 42.86 as he wandered disconsolately over the line – some way short of his world record personal best.

It was wretched luck for him.

"I was well prepared," said Robles.

"I started well, but when I went to change speed to attack the hurdle I felt a pain in the back of my thigh."

Brittney Reese of the United States performances a massive jump of 7.12m to claim long jump gold

The US gold rush was maintained in the final event to be decided, the women's long jump, where Brittney Reese – the young woman from Mississippi who has won two world indoor and two world outdoor titles since finishing fifth in Beijing - secured her title with a third round effort of 7.12 metres.

That left her five centimetres clear of the personal best of 7.07m set by Russia's Elena Sokolova, and a final effort of 6.89 by Reese's teammate Janay DeLoach took her past the first round leader, Latvia's 31-year-old Ineta Radevica, by just one centimetre.

The European champion, whose final effort of 6.79m confirmed the bronze went to the American, responded with customary grace in what must have been a moment of huge disappointment as she saw her first Olympic medal in a long career disappear.

Gold medalist Brittney Reese of the United States celebrates with teammate and bronze medalist Janay Deloach of the United States after the long jump

A US clean sweep on the night was only prevented by Russia's Natalya Antyukh, who moved past the United States' Lashinda Demus, who had made one of her trademark fast starts, in the final 50 metres to claim the 400m hurdles gold in a personal best of 52.70, the fastest time of 2012, with Demus clocking 52.77 and Zuzana Hejnova of the Czech Republic taking bronze in 53.38.

Earlier in the evening, a personal best of 88.34m put Vítězslav Veselý, the Czech Republic's European champion, into the javelin final as the top qualifier.

"Sometimes the qualification goes well and the final very bad," said the man who is trained by three-times Olympic champion Jan Zelezny.

"I hope that's not the case here.

"I'm confident, though, that I can repeat it."

Contact the writer of this story at [email protected]