Hellen Obiri upset Genzebe Dibaba to win the women's 5000 metres at the Diamond League meeting in Rome, while Andre De Grasse also starred.
Dibaba had her sights set on older sister Tirunesh's world record, but she fell well short and was upstaged by Obiri on Thursday.
Kenya's Obiri, the Rio Olympics silver medallist, surged clear to win in 14 minutes, 18.37 seconds - a national record and world lead - at the Stadio Olimpico.
Agnes Jebet Tirop and Letesenbet Gidey finished second and third respectively as Dibaba drifted back to sixth.
"When I came to this race, I told myself that nobody can beat me," Obiri said, via the IAAF.
"I thought Genzebe would push it forward but when she did not, I tried to do that myself.
"From the beginning, I was looking to the front, thinking about a time around 14:18. I even think I can improve it at the next competition."
De Grasse set a season's best in the men's 200m, an event in which he won silver in Rio, with a time of 20.01 seconds, edging Christophe Lemaitre (20.29secs) and Ameer Webb (20.33secs).
Dafne Schippers took out the women's 100m in 10.99 seconds, getting the better of Marie-Josee Ta Lou (11.03secs) and Michelle-Lee Ahye (11.07secs).
Sifan Hassan was the star in the 1500m, beating Winny Chebet and Konstanze Klosterhalfen.
Meanwhile, Conseslus Kipruto claimed victory in the men's 3000m steeplechase and Pole Adam Kszczot won the 800m.