Guinea-Bissau's Braima Dabo will not win any medals at the world championships but he won the admiration of the crowd on Friday by helping exhausted Aruban Johnathan Busby across the 5,000 metres finish line in an astonishing display of sportsmanship.

It was an agonising and heartwarming end to the opening heat of the men's 5,000m as a distressed Busby, near collapse, was rescued on the final lap by Dabo and helped home, with the two men crossing the line to a rousing ovation at Khalifa Stadium.

"The main objective was to represent my country as well as possible and I'm happy I could help the other guy," Portuguese-speaking Dabo told Reuters. "I saw he was not running in the right way, he was leaning, I realised he wasn't going to finish.

"I knew I wasn't going to beat my personal record, so when I realised that, it was better to go for the main aim, which was to finish the race. My thoughts were to help him finish, that is the point of the race."

Despite the searing temperatures in Doha, the race was run in pleasant spring-like conditions thanks to the innovative air-conditioning system at the Khalifa stadium.