An attempted pitch invasion delayed the men's 100m final, the chief Paris Olympics organiser said on Monday, explaining the long pause before the world's fastest men burst out of their blocks.
As millions watched around the world, organisers seemed to take an age to call the sprinters to the start line on Sunday night, building anticipation to fever pitch.
"There was an attempted pitch invasion at the 100m final," said Tony Estanguet, after images emerged on social media of security agents pinning someone to the ground on the edge of the track.
"The private security reacted very well. They are well prepared, they are rigorous, they are professional, and the police are doing a great job," added Estanguet.
He did not expand on the nature of the attempted invasion and it is not clear what the motive might have been.
The athletes waited a long time but Estanguet played down the incident.
"People are talking about four minutes but I've been told it's more like a minute and a half," he said.
"For one event, the last event of the evening, that's not too bad... they waited until everyone was ready to start this 100m race," added Estanguet.
The blue riband event was certainly worth the wait, US sprint king Noah Lyles blasting to gold in the closest race in modern Olympic history.
Lyles said he did not see the incident.