Ciara Mageean obliterated Sonia O'Sullivan's longstanding Irish mile record at the Diamond League meeting in Monaco on Friday evening as the Portaferry star filled the runner-up berth behind the remarkable Faith Kipyegon, who set her third world record in the last two months.
Mageean clocked four minutes 14.58 seconds, with O'Sullivan's previous best 4:17.25.
However, Kipyegon proved peerless in the principality, recording a scarcely believable time of 4:07.64. Sifan Hassan had set the existing world record of 4:12.33 over the same track in 2019.
Kipyegon lowered both the 1500m and 5,000m world records in June.
Kristie Schoffield of the United States and Uganda's Winnie Nanyondo both failed to finish the mile event, but they executed their role as pacemakers with aplomb.
The perfect fractions meant all bar one of the other 13 competitors set personal best times, with Mageean's the fifth-fastest time ever recorded. Freweyni Hailu of Ethiopia was the odd woman out back in third, but even her time of 4:14.79 constituted a season's best effort.
Mageean, whose previous best time was 4:19.03, was one of seven women in the field to set national records - including Laura Muir, who took over two seconds off Zola Budd's 38-year-old British mark - and four of those were also continental records.
"I think it's been my best season yet. I have opened it strong and have stayed consistent," Mageean said afterwards.
"Today I ran an Irish record over the mile. I am really proud of myself for that. I feel I am in a really good place to go to the World Championships.
"Sometimes when you know you are in good shape, it's a bit more scary because you really know that you can achieve your goals."
Her compatriot Rhasidat Adeleke was fourth in the 400m after clocking 49.99 from lane five as Poland's Natalia Kaczmarek finished with a flourish to prevail in 49.63.
The Irish record holder made a huge move approaching the final bend and looked certain to secure a podium place before flagging late on.
Shamier Little of the United States secured second ahead of Lieke Klaver of the Netherlands, with Adeleke and the Dutch competitor recording identical times.
Despite a sluggish start, Sarah Lavin sizzled to a time of 12.74 in the 100m hurdles from lane six as the Limerick athlete finished seventh behind former world champion Nia Ali.
Lavin's time was just one hundredth of a second off the personal best she set in Stockholm at the beginning of the month, while Ali's winning time of 12.30 is the fastest run in the world this year.
