Since former champion Dawn Harper Nelson (season best 12.63) won the heat, the Americans have four in the final and could sweep the medals again - like they did past year at the Rio de Janeiro Olympics.
Coburn finished third in the Olympic final a year ago though was only an outsider for the title here, with the likes of Jepkemoi and Jebet considered the favorites, though in a dramatic race the American stayed calm to set a new Championship record with a time of 9:02.58.
Surprisingly, on the final lap it was world record holder Jebet who began to fall away first, and with Chepkoech falling behind at the water jump, it was here when Coburn made the decisive move. Olympic bronze medalist Emma Coburn and fellow Olympian Courtney Frerichs changed that with a 1-2 finish to capture gold and silver in the world championship final at London's Olympic stadium. She sealed her victory with a surge after the final water barrier.
"What a race to be part of", said Coburn.
Beatrice Chepkoech of Kenya, the third best performer this year, was running in the lead at the start when she missed the turn for the water jump on the inside of the track and had to go back. "It is pretty awesome to get a championship record", she added. She just 24 years old, won an NCAA title in 2016 as a member of the New Mexico Lobos and the qualified for the Olympics, where she finished 11th in the final.
China still building islands in disputed South China Sea: security think tank
The expert also shared his thought on the possibility of an open military confrontation in the South China Sea. On Thursday, he suggested that he might spare China trade penalties if it did more to curtail North Korea.
"I was expecting a challenge from when I hit the front".
American Kimberlyn Duncan finished just behind Stevens in sixth.
Ivorian Marie-Josée Ta Lou was only beaten to the 100m gold medal by a diving Tori Bowie of the United States, while Shaunae Miller-Uibo of The Bahamas was attempting to banish the demons of the unforgettable finish to the 400m two nights ago. She ran an incredible race to get the championship record.
Schippers used her long, powerful stride to nudge clear of the rest of the field to claim her fifth World Championships medal. The Americans went very fast, as you saw with the championship record. Kenya's Conseslus Kipruto won gold.
Poland are the surprise occupant of third place having won two medals of each colour so far.