As defending champion and world record holder, it was McLaughlin-Levrone who entered their latest meeting as favourite, hinting at this form by improving her best time two months ago.

However, Bol had shown progress of her own, setting an indoor 400m flat world record this year and a new European 400m hurdles record of 50.95 in July to become only the second woman to run under 51 seconds over the barriers.

Bol produced a sensational sprint finish to take the Netherlands from fourth place to gold in the mixed 4x400m relay earlier in the Games, but on this occasion the 24-year-old did not have the legs to trouble a jubilant McLaughlin-Levrone.

"My whole family's here. We're going to celebrate, we're going to enjoy this time and get ready for the relay too," said McLaughlin-Levrone, who celebrated her 25th birthday on Wednesday.

"It's amazing to see our sport continue to grow, for people to want to watch the 400m hurdles, it's amazing."

She spoke of what it had taken to achieve her gold mission, saying: "Just a lot of hard work put in this year. I knew it was going to be a tough race. An amazing competition all the way round."

Elsewhere, Arshad Nadeem made history by winning Pakistan's first Olympic gold in athletics - throwing a Games record of 92.97m in the men's javelin.

USA's Grant Holloway beat compatriot Daniel Roberts to take the men's 110m hurdles title and upgrade his silver from Tokyo, while another American - Tara Davis-Woodhall - won the women's long jump.