After the race was given the early-morning green light following pollution tests, Beaugrand was among the leaders from the start and then put the hammer down with a kilometre of the 10km run to take gold, breaking the tape in 1:54:55s.

Julie Derron continued Switzerland’s rich pedigree in women’s Olympic triathlon, coming in 6s behind to add a silver to the golds of Brigitte McMahon in 2000 and Nicola Spirig in 2012.

World champion Potter also built on Britain’s record as the most successful nation in the sport, with her bronze a further nine seconds back making it nine medals for the country in all.

After the postponement of the men’s race yesterday due to poor water quality, the women’s event got underway on time on the back of a rainstorm.

Defending champion Flora Duffy, the winner of Bermuda’s only Olympic gold and appearing in a remarkable fifth Olympics at the age of 36, led the 1,500m Seine swim out.

All the main contenders were in a group of nine that picked Duffy up but the morning’s heavy rain, combined with several cobblestone sections, made the bike leg treacherous and there were a series of crashes.

The leaders – with the exception of Germany’s Laura Lindemann – negotiated the seven-lap 40km route safely and, without any hills to break them up, arrived en masse for the 10km run.

After the first of four 2.5km laps, however, Potter, Derron, and local favourites Emma Lombardi and Beaugrand had forged clear.

The quartet ran together until halfway round the final lap when Beaugrand made her decisive move and was able to enjoy the greatest moment of her career.

Lombardi was a frustrated fourth while Duffy, despite being out for a year with a knee injury, also ran well for an impressive fifth.

Britain’s Tokyo silver medallist Georgia Taylor-Brown finished sixth.

The men’s race is due to go off at 10.45am today.