Dutch flier Dafne Schippers completed her transformation from heptathlete to world champion sprinter when she ran the fourth fastest 200 meters of all time to win by a nose at the Bird's Nest on Friday.
The 23-year-old European champion clocked 21.63 seconds to beat Jamaica's Elaine Thompson by three-hundredths of a second and add gold to the silver medal she won in the 100m behind Shelly-Ann Fraser-Pryce on Monday.
Only Americans Florence Griffith-Joyner, the world record holder, and Marion Jones, who was later banned for doping, have run faster.
"I can't believe it," Schippers, who only switched her focus to the sprints full time this year, told reporters.
"What a race! What a tournament for me! I think they'll be going crazy in the Netherlands at the moment."
Twice Olympic champion Veronica Campbell-Brown took bronze (21.97) in a race which featured two of the five fastest 200 meters of all time and six of the seven fastest of 2015.
Aries Merritt's achievement in winning bronze in the 110 meters hurdles was perhaps the most impressive of the night, however, given the Olympic champion will undergo a kidney transplant on Tuesday.
The world record holder finished third behind Russian Sergey Shubenkov and the delighted 30-year-old explained why his sister was not cheering him on at the Bird's Nest.
"It almost means more to me than my Olympic gold, the state I'm in, the training I've done, it's been very difficult. The struggle is real," Merritt said.
"My sister's going to give me one of her kidneys. That's why she didn't come to Beijing, she did not want to endanger the transplant."
Jamaica's Danielle Williams had her sister Shermaine alongside her when she enjoyed the finest moment of her career with a shock win in the women's 100 meters hurdles.
It was the first time siblings had competed in a world championship final and it was the younger sister who stormed to victory in a personal best 12.57 seconds ahead of Germany's Cindy Roleder and Alina Talay of Belarus.
Williams did benefit from three of the American favorites succumbing to the pressure, two going out in the semi-finals and the other clipping her first hurdle, but nothing was going to deny her family their delight.
"It was so special that we were together in this final," said Danielle, whose sister finished seventh.
"There will be a big celebration for sure, my family is shouting, celebrating -- they look even happier than I am."
Decathlon world record holder Ashton Eaton may feel he has family pride to restore after his wife Brianne Theisen-Eaton failed to live up to her favorites tag and settled for silver in the heptathlon.
Eaton clocked the fastest 400 meters of all time in the multi-discipline event (45 seconds) to lead the competition after five events with 4,703 points ahead of Canadian Damian Warner (4,530) and Rico Freimuth of Germany (4,406).
"No way in hell did we think I was running that fast," he told reporters.
"I thought 46-flat, maxed out. You know me. I just go and don't hold too much back (and) it turned out something unbelievable."
There was disbelief for Shubenkov too after he beat Hansle Parchment of Jamaica to the line in a Russian record for the 110m hurdles of 12.98 seconds.
"I don't remember anything about the race. I heard the starting gun and then I opened my eyes and it was finished," he said.
"I wondered whether it was really happening, whether I might wake up. This is the best day of my life."
Tianna Bartoletta rolled back the years in the women's long jump, snatching a second world title with a leap of 7.14 meters a decade after she won her first under her maiden name Madison.
The American's best jump was her last and Britain's Shara Proctor, who had led the competition after breaking her own national record with a 7.07m jump in the third round, fouled with her final effort.
China's Liu Hong and Lu Xiuzhi looked a little like siblings as they matched each other stride-for-stride until the last few steps of the 20km walk.
Liu led Lu over the line in a time of one hour 27 minutes and 45 seconds for the first gold of the day, to the delight of the crowd basking in the morning sunshine.
"I felt a lot of pressure. China had not won a gold medal and everybody was waiting for it," Liu said.
Russian walker Alexander Yargunkin will not compete in the men's 50km walk on Saturday after being suspended while the Russian anti-doping agency (RUSADA) investigates media reports he tested positive for blood-boosting agent Erythropoietin.
It will be the first time no Russian walkers will take part in a world championships.
(By Nick Mulvenney; Additional reporting by Gene Cherry and Dmitriy Rogovitskiy, editing by Ed Osmond)