Karsten Warholm's hopes of winning a third straight World Championships title were dashed while Britain's Jake Wightman felled reigning Olympic 1,500-meter champion Jakob Ingebrigtsen on a day of upsets Tuesday.
Kristjan Ceh dethroned Olympic champion and 2019 winner Daniel Stahl in the discus final and Eleanor Patterson outdid Yaroslava Mahuchikh to win women's high jump gold.
Norwegian Olympic champion Warholm, who tore his hamstring at the Rabat Diamond League meet in June, struggled down the final meters of the 400-meter hurdles to finish seventh as Brazilian Alison dos Santos took gold in 46.29 seconds.
America's Rai Benjamin took silver, with his compatriot Trevor Bassitt claiming bronze.
In the 1,500-meter, Wightman took a surprise gold as he beat hot favorite Ingebrigtsen, with his father Geoff calling him home as the Hayward Field stadium announcer.
"That's my son and he's world champion," Geoff told the Hayward Field crowd.
Wightman went past the Norwegian on the back straight of the final lap, crossing the line in 3:29.23, the fastest time in the world this year. Ingebrigtsen took silver while bronze went to Spain's Mohamed Katir.
Slovenia's Ceh put in the performance of his life to beat Stahl, who finished fourth, and win discus gold with a 71.13-meter attempt. Lithuanian duo Mykolas Alekna and Andrius Gudzius finished with silver and bronze respectively.
Australian Patterson produced a lifetime best leap as she cleared an Oceania record of 2.02 meters in the women's high jump to win ahead of Ukrainian favorite Mahuchikh, with Italy's Elena Vallortigara taking bronze.
Earlier Tuesday, reigning champion Noah Lyles and 18-year-old sensation Erriyon Knighton set up a highly anticipated showdown in the 200-meter finals, while 100-meter winner Fred Kerley's bid for a sprint double ended when he finished sixth in his heat.
The women's 200-meter event produced a stunningly-fast trio of semifinals, which saw four women miss out despite running times that would have qualified for every previous final.
The women's discus throw and women's 3,000-meter steeplechase finals will take place Wednesday, as well as the semifinals for the men's and women's 400-meter.