Noah Lyles thought he had shattered the 200 metres world record on Thursday, but the American's joy was short-lived as it transpired he had not run the full distance.
Lyles, running on his own in Florida as part of the Inspiration Games event, crossed the line in a rapid 18.90 seconds.
It appeared the record of 19.19s Usain Bolt set at the 2009 World Championships had gone, but BBC commentator Steve Cram was among those to question the time.
"That cannot be right," said Cram. "Even he has got his hands in the air wondering what is going on."
It was then revealed that world champion Lyles had run 15m less than his opponents competing at other tracks, as he had started in the wrong lane.
The 22-year-old subsequently missed out on a $10,000 winner's cheque, with Christophe Lemaitre taking victory in a time of 20.65 at Letzigrund.
Lyles tweeted: "You can’t be playing with my emotions like this.... got me in the wrong lane smh [shaking my head]."