"I'm not surprised to have won the race or to the time. I have prepared very well," Marileidy Paullino told the organizer after 49.12, which was 0.14 above her world best.
McLaughlin-Levrone was second in 49.71, the first time she ran under 50 seconds. But with a world record in the hurdles of 50.68, there were much greater expectations.
Naser back after doping suspension
Things looked to be going according to plan until the start of the riot when McLaughlin led clear but then the claw came and she started treading air. With a much better organized race, this year's world number one Marileidy Paullino stepped past and won clearly.
Third was Salwa Eid Naser in 49.95 – her second event after the doping suspension for misses in stay reporting. Earlier this week, she ran in 49.78. The Bahraini runner made a sensation at the 2019 World Championships in Doha by winning in 48.14.
Keely Hodgkinson won the 800 metres in a British national record of 1:55.77 and beamed afterwards.
"I'm kind of in shock that I was able to run so fast," Hodgkinson told organizers.