Kenya's Faith Kipyegon set a new 1500m women's world record as she blew the competition out of the water at the Diamond League meeting in Florence.
Storming clear of British runner-up Laura Muir during the final lap, Kipyegon - the reigning world and Olympic champion - crossed the line with 3:49.11 on the clock.
The astonished Kipyegon broke the previous record of 3:50.07, which was achieved by Ethiopia's Genzebe Dibaba in Monaco back in July 2015.
The 29-year-old was mobbed by her fellow competitors as she celebrated becoming the world record holder for the first time, while Muir's season's best time of 3:57.09 was good enough for silver.
Australia's Jessica Hull was just behind Muir in the bronze medal position with a time of 3:57.29, while the Republic of Ireland's Ciara Mageean (4:00.95) finished fourth.
Elsewhere, Great Britain's Dina Asher-Smith was due to compete in the women's 100m race, but the 27-year-old had to pull out at the last minute due to cramp.
