In the first heat of the men's 5000m, there were just two athletes left on the track.
Aruba's Jonathan Busby was suffering all too visibly on the last lap, but luckily Braima Suncar Dabo of Guinea-Bissau was on hand to help.
As his fellow competitor staggered on jelly legs, Dabo held his arm to try and support him.
With just over 100m to go, Dabo moved Busby's arm up around his neck to assist him further as the crowd cheered his selfless act of generosity and sportsmanship.
Eventually they made it to the line with Busby stopping the clock on his wristwatch before collapsing through exhaustion.
"Anyone in that situation would do the same"
Dabo's effort, officially anyway, was in vain as Busby was disqualified for receiving outside assistance.
He was not the only one with European champion Jakob Ingebrigtsen eliminated for stepping on the inside of the track.
Norway have appealed the decision with the 19-year-old hoping to join his two brothers - Filip and Henrik - in Monday's final.
Back to Dabo whose actions won the hearts of those inside the Khalifa International Stadium, and the admiration of millions watching on television around the world.
Speaking to reporters afterwards, the 26-year-old said, "I had my goals to represent my country as well as possible and also fight for my personal record. And when there were three laps to go, I realised that I couldn't beat my best of 17:30.
"We were the only ones on the track and I thought it was better to help him than to get past him. I think anyone in that situation would do the same."