Meanwhile, reigning world champion Bol – who won in Budapest last year in McLaughlin-Levrone’s absence – ran 53.38 to go fastest overall, with both easily capable of going at least a second quicker once the heat turns up.
The repechage round takes place on Monday morning, with the semi-finals on Tuesday evening before the women’s 400m hurdles final is held on Thursday (8 August).
Rushell Clayton will be out to prove she is not merely the best of the rest behind Bol and McLaughlin-Levrone, and the Jamaican was the first contender to take to the track on Sunday.
In the first of five heats, Clayton – bronze medallist in the worlds last year – crossed the line first in 54.32.
USA’s Jasmine Jones then won the second heat, outlining her podium potential with a 53.60, before Bol - fresh off the back of winning gold in the 4 x 400m relay - went out next to huge cheers at the Stade de France.
Bol had come flying back to win a thrilling gold for the Dutch on the final relay leg on Saturday night, and this time around she managed her energy and coasted over the line in first with a time of 53.38.
“I would like to sleep now!” Bol, who ran 50.95 in July, told BBC. “I really feel the Olympic spirit, it feels so amazing, but now I have enough time to rest.”
American Anna Cockrell then joined compatriot Jones in winning her heat, telling Olympics.com afterwards: “That was good, it was very exciting. I feel really good, a couple of things to clean up.
