American Kerron Clement thought he might finish his 400 metre hurdles final diving for the line like Shaunae Miller as the lactate built up in his legs.
Clement led throughout Thursday's final inside the Olympic Stadium and looked certain to take gold as he led going into the last 100m.
The 30-year-old did manage to hold on, but he was pushed all the way to the line by Kenya's Boniface Tumuti and Yasmani Copello of Turkey.
While he may have looked in control, Clement admitted he was struggling in the closing stages and thought he may end up copying Miller's dive for victory - the Bahamian having claimed the 400m title in dramatic fashion on Monday.
"I came out here with one mindset and that was to execute my race plan and trust my fitness and just believe in myself," said Clement.
"I knew the last 100 metres would be tough and those guys would be coming the last 50 metres.
"I felt the lactate in my legs and I thought about diving like the Bahamas runner [Miller] but I dug down deeper to get that win and my first individual gold medal.
"It is a surreal feeling."
And Miller was well prepared for his victory lap, having predicted his victory and instructed his mum to bring an American flag for him to celebrate with.
He added: "It was a great honour for my mum who gave me the flag to run around the stadium because she was here to witness history.
"Before we left the States I told her 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."