States to a sixth consecutive victory in the men’s final.
Merritt, David Verburg, Tony McQuay and Bryshon Nellum finished in 2:57.82 to extend a remarkable winning streak dating back to Helsinki in 2005. Trinidad and Tobago claimed silver in 2:58.20 with Britain taking bronze in 2:58.51.
Kenya’s demonstrated their middle-distance brilliance again when Asbel Kiprop completed a world title hat-trick in the men’s 1,500m to add to the 800m gold won by David Rudisha earlier in the competition.
Kiprop, who also won gold at the Bird’s Nest in 2008, surged home in 3:34.40 in an electrifying finish, just edging out his countryman Elija Manangoi. Morocco’s Abdalaati Iguider darted past Algeria’s Olympic champion Taoufik Makhloufi to take bronze.
“I’m so proud of myself to become a member of this exclusive club of three-times world champions,” said Kiprop. “I came here not to run but to win. It was very special. I never panic, it was a fast last lap and I knew I was good on the finish. I executed well.”
Ethiopia’s Almaz Ayana upset countrywoman Genzebe Dibaba in the women’s 5,000m, denying her a golden double following her victory in the 1,500m.
Ayana clocked a championship record of 14:26.83 with Senbere Teferi taking silver in 14:44.07, a whisker ahead of Dibaba in an Ethiopian sweep of the podium.
In the final field events, Canada’s Derek Drouin claimed the men’s high jump world title in a cliff-hanging contest.
The Commonwealth Games champion cleared two metres, 34 centimetres as a partisan Beijing crowd roared on local favourite Zhang Guowei, who shared silver with Ukraine’s title-holder Bohdan Bondarenko after going over at 2.33m.
“It’s really beautiful to own this title,” said Drouin. “I knew I was in good shape but hoping to win and making it actually happen are two different things.”
Meanwhile, Germany’s Kathrina Molitor broke Chinese hearts by winning her first major javelin title at the age of 31, with Lyu Huihui taking silver.