The 19-year-old prodigy from New Jersey, who only turned professional in June after a successful college career, led from start to finish to win in a new US national record of 1:55.21s.

Britain’s Keely Hodgkinson – another 19-year-old – took silver in 1:55.88s while Raevyn Rogers of the US took bronze in 1:56.81s.

Mu, whose parents moved to the US after fleeing civil war in Sudan, is the first American woman to win the Olympic 800m title since Madeline Manning won gold at the 1968 Mexico City Games.

It was a remarkable display from Mu, showing a confidence and maturity that belied her relative inexperience in top level track and field.

Drawn in lane three, Mu glided into the lead before the 200m mark and never looked back, clocking a brisk 57.82s first lap.

She then cranked up the pace in the closing 200m, pulling away from the field to cross the line with a comfortable margin of victory from the fast-finishing Hodgkinson.

This year’s Olympic 800m took place in the absence of 2012 and 2016 gold medallist Caster Semenya of South Africa.

Semenya has been barred from competing over 800m by World Athletics’ testosterone-reducing regulations.