Faith Kipyegon made history at the Florence Diamond League on Friday by breaking the symbolic 3min 50sec barrier while setting a new world record for the women's 1500 metres.
The 29-year-old Kenyan clocked 3:49.11 to shatter the previous record of 3:50.07 set by Ethiopia's Genzebe Dibaba in Monaco in 2015 in an awesome display from the two-time Olympic and world champion.
Kipyegon, considered the greatest ever woman in the discipline, crushed the rest of the field in Tuscany, finishing more than 12 seconds ahead of reigning European champion Laura Muir and Australia's Jessica Hull.
She fell to her knees in joy and disbelief after conquering the record, the only major honour she had been without despite her stellar career.
"I'm so excited, so happy, I didn't expect this. I was expecting a world lead, not a world record, but I'm so grateful," Kipyegon said to broadcaster RAI.
"As I said today and yesterday everything is possible."
World champion Fred Kerley eased to victory in the men's 100 metres, again in the absence of injured Olympic champion Marcell Jacobs.
American Kerley crossed in 9.94sec, but insisted victory en route to a bid for a 100-200m sprint double at the world championships in Budapest in August was more important than the far from stellar time.
African champion Ferdinand Omanyala, who has run the fastest time of the season thus far when he hit 9.84sec in Nairobi, was second, at 0.11sec, the Kenyan having also finished on Kerley's coattails in Rabat last week.
"The most important thing was the win today, I ran like I wanted to today," Kerley said.
"My ultimate goal is to get double goal in Budapest and all this is steps towards the ultimate one."
- No Jacobs again -
Kerley won in Rome last year in 9.92sec before conquering the US championships and taking the world gold in Eugene.
His fellow Americans Marvin Bracey and Trayvon Brommell, who finished on the podium behind Kerley at the worlds, finished last and third respectively.
Jacobs didn't race on home turf as he pulled out of the event with a back injury as he did in Rabat.
There has not been a showdown between Jacobs and Kerley since the Italian trumped Kerley for a shock gold at the Tokyo Olympics, pushed back a year to 2021.
Teen sensation Erriyon Knighton easily won the 200m, crossing the line in a season's best 19.89sec, 0.39sec ahead of nearest challenger Jereem Richards.
Knighton, 19, is a rising star of American sprinting and holds the 200m world records for under-18 and under-20 athletes.
"It's a good time for a season opener, I feel like I did good, could have been better but I'm happy with the result," Knighton said.
Femke Bol charged to a season-leading 52.43sec in the 400m hurdles as the reigning Diamond League and European champion eyes gold at the Budapest worlds later this year.
"I am really, really happy, I executed the race like I wanted. It was a strong field which pushes me even more," said 23-year-old Bol.
"At the World Championships I have the chance to win a gold medal... So today's time is nice, but this year is all about Budapest."
British sprinter Dina Asher-Smith didn't take part in the women's 100m, won by Marie-Josee Ta Lou in 10.97sec.
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