Paula Radcliffe has seen her 16-year-old women's marathon world record shattered by Brigid Kosgei as the Kenyan set a new mark of two hours, 14 minutes and four seconds in Chicago.
Less than 24 hours after compatriot Eliud Kipchoge became the first athlete to break the two-hour barrier in Vienna, Kosgei made more history by beating Radcliffe's time by one minute and 21 seconds.
Radcliffe, who was present at the finish line to congratulate Kosgei, had recorded her winning time in London in April 2003 and it had proven unbeatable until the Kenyan ripped up the record books.
But it was a bad day for defending Chicago champion Mo Farah, who finished more than four minutes behind the winner of the men's race, Lawrence Cherono, who sprinted home in two hours, five minutes and 45 seconds.
Kosgei, the defending Chicago champion who also won the London Marathon last year, said she had not set out with the expectation of eclipsing Radcliffe's historic mark.
"I am feeling good and happy because I was not expecting to run like this," said Kosgei. "But the course is good and I was able to run my best time."
But after passing through the halfway point in 1.06.59, well inside world record pace, Kosgei maintained her pace and crossed the line almost seven minutes in front of second-placed Ababel Yeshaneh of Ethiopia.
Radcliffe had set her first marathon world record in Chicago in 2002 before lowering the mark in London the following year to the one that would prove persistently impossible to beat.
Radcliffe said: "We always knew the time was going to come and when I saw how fast Brigid was running in the first half of race I knew if she was going to hold it together she would do it.
"It was exactly 17 years ago today that I set my first world record in Chicago. That was a very special day for me and it is a very special day for Brigid today."
Farah endured a day to forget as he found himself cast adrift by the halfway stage of his title defence and eventually finished in a disappointing two hours, nine minutes and 58 seconds.
Farah had sparked controversy in the pre-event build-up when he implied there were racial elements in questioning over his relationship with the disgraced coach Alberto Salazar.
Cherono won a dramatic sprint finish to take his second major marathon title of the year in front of Ethiopian pair Dejene Debela and Asefa Mengstu.