Qatar's Saif Saaeed Shaheen retained his world 3,000 metres steeplechase title with a victory over his great rival and former Kenyan compatriot Ezekiel Kemboi yesterday.
World record holder Shaheen, formerly known as Stephen Cherono, produced a telling burst of speed on the final lap to win in eight minutes 13.31.
Olympic champion Kemboi took silver in 8:14.95 with team-mate Brimin Kipruto grabbing bronze in 8:15.30.
Also yesterday, American Bershawn Jackson won the world men's 400 metres hurdles title after defending champion Felix Sanchez failed to finish.
Sanchez, bidding for a third successive title, pulled up clutching his right hamstring after the first barrier in a race run on a soaking track in pouring rain.
Earlier on, a violent thunderstorm had halted competition and forced the postponement of the women's discus final until tomorrow.
Organisers said the men's triple jump qualifying and 200 metres quarter-finals would be staged today.
The storm struck after the first heat of the women's 100 metres hurdles and sent athletes and officials scurrying from the Olympic stadium.
The 22-year-old Shaheen, who emigrated to Qatar for economic reasons two years ago, is unbeaten in the steeplechase since 2002.
"Well I feel great," he said.
"This is a consolation for missing the Olympics. I want to win more in my career and prepare for the Olympics in China in 2008."
Shaheen was banned from competing for Qatar at the Athens Games by his former federation leaving Kemboi to lead home a Kenyan clean sweep of the medals in his absence.
Two years ago in the Paris world final the pair had fought out an epic duel with Shaheen, seemingly-beaten in an all-out sprint, conjuring one last burst to haul back his rival.
This time, with rain drenching the Olympic stadium, Shaheen toyed with Kemboi, testing him on the penultimate lap with a surge of pace before slowing down as they approached the bell.
Kemboi gave valiant chase in the final 400 metres but a confident Shaheen could afford to glance up at the stadium's big screen down the back straight before pulling away off the bend.
Jackson, 22, won in a surprisingly fast 47.30 seconds after overtaking compatriot James Carter in the final straight.
Japan's Dai Tamesue prevented an American sweep in third place ahead of US champion Kerron Clement.
The trio of Americans and Tamesue braved the torrential rain to jog the customary lap of honour in front of an appreciative crowd.
Olympics champion Sanchez has been struggling with a foot injury this season.
The 27-year-old from the Dominican Republic did not look comfortable in the previous round, qualifying as a fastest loser, and false-started in the final.
It was a first major medal for Jackson, who is easily recognisable on the track by his distinctive head band which he wears in memory of his uncle Richard who encouraged his career in athletics.
Cuban claims 800m race
Zulia Calatayud stormed to victory in the women's 800 metres. The Cuban powered down the straight to win comfortably in a time of one minute 58.82 seconds.
Olympic silver medallist Hasna Benhassi of Morocco took the silver medal in 1:59.42 and Russian Tatyana Andrianova the bronze in 1:59.60.
Briton Kelly Holmes, the Olympic champion, missed the world championships through injury.