Norway's Jakob Ingebrigtsen set a new European record in the men's 5000m at the Golden Gala Diamond League meet in Florence on Thursday (10 June).
The 20-year-old took some 14 seconds off his lifetime best in clocking 12:48.45, breaking a 21-year-old record previously held by Belgium's Mohammed Mourhit.
It was a hotly-anticipated contest against the world record holder, Uganda's Joshua Cheptegei, but Cheptegei pushed too hard early and fell back on the final lap to only cross the line in sixth place.
Ingebrigtsen's mark was also the world leading time in 2021, one of multiple world leads set in Florence.
Dutchwoman Sifan Hassan clocked the fastest women's 1500m of the season in a tight head-to-head with Kenya's Faith Kipyegon.
Hassan crossed the line in 3:53.63, barely three-tenths against Kipyegon whose 3:53.91 was a new Kenyan national record.
"I thought that Faith Kipyeon was going to win," Hassan said after her race. "At 800m we were so fast, but I tried to do my best. I got the MR (meet record), but for me it is not so much about the MR. I am surprised about the time!"
Olympic men's 110m hurdles champion Omar McLeod also set a world lead in his event, crossing the line in 13.01.
There was disappointment for another Olympic champion, Conseslus Kipruto, who failed to finish the men's 3000m steeplechase. That race was won in a world-leading 8:08.54 by Morocco's Soufiane El Bakkali.
Other stars who clinched victory on the day included Great Britain's women's 200m world champion Dina Asher-Smith (22.06), and double Olympic champion in the women's discus Sandra Perkovic of Croatia (66.90m final, 68.31m best).
South Africa's Akani Simbine (10.08) won the men's 100m in the evening's last race.