Ghirmay Ghebreselassie from Eritrea, competing in only his fourth marathon, collected the first gold medal of the meeting after completing the 42 kilometres in 2 hours 12 minutes and 27 seconds.
The Ethiopian Yemane Tsegay was second and Munyo Solomon Mutai from Uganda took the bronze medal.
Defending champion Stephen Kiprotich finished ninth and the pre-race favourites, world record holder Dennis Kimetto and his Kenyan compatriot Wilson Kipsang Kiprotich, failed to last the distance.
While they floundered in the heat of Beijing, 19-year-old Ghebreselassie displayed a cool maturity. He took the lead from Lesotho's Tsepo Ramonene Mathibelle on the 36km mark and saw off pressure from Tsegay on the approach to the finish line to pocket the biggest prize of his nascent career.
It was only the second medal Eritrea had won at the world championships. And it might have never come had Ghebreselassie followed the advice of his parents. They wanted him to continue with his education and go to university.
“They didn’t accept me as a runner,” he said. “I had potential at school and they wanted me to go to university. They wanted me to get the best start in life. But when I started to show them my achievements in athletics, they started to support me especially when I had to go abroad. They believed I could make a special history.”
Theirs was faith well placed. Ghebreselassie is the youngest winner of the men’s marathon at the world championships since its inception in 1983.
He is also the first Eritrean to win a world championship gold medal and after victory over an accomplished field he set his sights on Olympic glory in Rio next year.
“My first marathon was in Chittagong, the second was in Dubai and I didn’t finish that,” he added. “But I ran in Hamburg and I’ve won here in Beijing. If you work hard it’s possible to achieve what you want to do.”