American Sydney McLaughlin shattered her own 400 metres hurdles world record to clinch her first individual World Championships gold, while compatriot Michael Norman claimed the men's 400m crown and Bahamian Shaunae Miller-Uibo won the women's event.
McLaughlin blazed home in 50.68 seconds to set the first world record at this year's championships, finishing well clear of silver medallist Femke Bol of the Netherlands. Defending champion Dalilah Muhammad finished third.
"The time is absolutely amazing and the sport is getting faster and faster," said McLaughlin, who won 4x400m world relay gold in Doha. "Just figuring out what barriers can be broken. I only get faster from here."
Miller-Uibo cruised to 400m gold in 49.11 seconds to win her first world title, adding to her two Olympic gold medals from 2016 and 2020 over the distance. Dominican Republic's Marileidy Paulino, silver medallist behind Miller-Uibo in Tokyo, had to settle for second place again while Sada Williams of Barbados took bronze.
In the men's event, Norman made up for a disappointing fifth-placed finish in Tokyo by winning gold in Eugene, charging to victory in 44.29 seconds for his first world crown.
Former Olympic and world champion Kirani James of Grenada was runner-up while Britain's Matthew Hudson-Smith held off Champion Allison to take the final podium place. "Last year was not a good year for me so I had to do a lot of hard work just to get back to where I was," Norman said. "This moment is going to be remembered forever."
Tokyo bronze medallist Kelsey-Lee Barber joined 400m runner Cathy Freeman as the only Australians to retain a world athletics title after defending her javelin crown with a world-leading throw of 66.91m.
American Kara Winger (64.05) and Japan's Haruka Kitaguchi (63.27) snatched silver and bronze with their last-round throws.
The American men's relay quartet of Christian Coleman, Noah Lyles, Elijah Hall and Marvin Bracy cruised into the 4x100m finals in 37.87 seconds, and the U.S. women's team also had little trouble, finishing fastest in 41.56 seconds.
Reigning world champions Jamaica qualified without Shericka Jackson, Shelly-Ann Fraser-Pryce and Elaine Thompson-Herah, who swept the 100m podium.
Allyson Felix postponed her retirement plans after being called up for Saturday's 4x400m relay preliminaries, having brought the curtain down on her glittering career last week.
Peru's Kimberly Garcia Leon won the inaugural 35km women's race walk in 2:39:16, a week after claiming her first world gold over 20km. Katarzyna Zdzieblo of Poland and China's Qieyang Shijie also mirrored their results from the 20km race walk by finishing second and third.