Saif Saaeed Shaheen won the 3,000 metres steeplechase final to give Qatar their first ever World championship medal.
Born in Kenya and formerly known as Stephen Cherono, Shaheen was granted citizenship of the Gulf state earlier this month.
He held off his former Kenyan team mate Ezekiel Kemboi in a sprint to the line to win in eight minutes 04.39 seconds on Tuesday.
Kemboi took the silver in 8:05.11 and Spain's Eliseo Martin was third in 8:09.09.
Defending champion Reuben Kosgei of Kenya dropped out of the race with 3-1/2 laps to go.
Shaheen's elder brother Abraham Cherono, running for Kenya, was fifth.
Shaheen's victory took the title away from Kenya, who had won it at the last six.
Photograph: Getty Images
