After holding off the late charge of Kenya’s eventual silver medallist Boniface Tumuti, who set a national record of 47.78, the 30-year-old American, who won the 2007 and 2009 world titles and took Olympic silver in 2008, revealed: "Before we left the States I said to bring a flag because I knew I was going to win.

“I made a space on my cabinet where I have all my medals and the space in the cabinet reads 'gold medal 2016'.

“So I knew I was coming here to win the gold medal."

But translating ambition into actuality pushed this experienced athlete to the edges of his endurance in a race where the five runners behind him all set either national records or personal bests.

"I knew the last 100m would be tough and those guys would be coming the last 50," he said.

"I felt the lactate in my legs and I thought about diving like the Bahamas runner [Shaunae Miller] but I dug down deeper to get that win and my first individual Olympic gold medal.”

Clement, who won gold at Beijing 2008 as part of the US 4x400m relay team, added: "I knew I had the fastest speed out of the last hurdle and I knew without a doubt that no-one would sprint me down on that last 50m. 

"I was sprinting for my life."

Bronze went to Yasmani Copello of Turkey in a national record of 47.92, just ahead of the Irish runner who has been battling against a hip injury this season, Thomas Barr, who clocked a national record of 47.97.

Behind him, Jamaica’s Annsert Whyte ran a personal best of 48.07, ahead of Estonia’s Rasmus Magi, whose 48.40 was also a national record.

As Clement lay on the track contemplating life as Olympic champion, he was congratulated by his team-mates Ashton Eaton and Jeremy Taiwo, who dashed over between throws as they competed in the second of the decathlon discus qualifying groups.

Clement is a part-time model and appeared in Beyonce's "Run The World" music video. 

This isn't going to do his celebrity profile any harm at all...

There was high drama on the track earlier as the US women’s 4x100m team - who won the London 2012 title in a world record of 40.82sec - were disqualified from their heat after the baton was dropped in the second exchange between Allyson Felix, who won silver in the 400m final here, and English Gardner.

But the US quartet won an appeal, claiming Felix had been bumped by a Brazilian runner in the next lane, and they were given the chance to earn a qualifying time all by themselves later today, with a target of 42.70.

The Brazilian 4x100 team was disqualified.

The US were top qualifiers in the men’s 4x100m heats, with a time of 37.65 ahead of Japan, who clocked an Asian record of 37.68, and China, whose time of 37.82 in the first heat was also an Asian record until the Japanese eclipsed it.

Britain’s quartet reached the final as one of the fastest losers in 38.06.

Both sprint relay finals are tomorrow.

All the big guns qualified from the men’s shot put ahead of tonight’s final, with US thrower Ryan Crouser topping the list with 21.59, and it was the same in the women’s high jump qualification ahead of Saturday’s final.

Meanwhile, Eaton remained on track for his attempt to become the first decathlete since Britain’s Daley Thompson in 1984 to retain the Olympic title.

After this morning’s 110m hurdles and discus he led the standings after seven of the 10 events with 6398, ahead of Canada’s Damian Warner on 6283) and Kevin Mayer of France who has 6211.