In effect, however, when Sha’Carri Richardson and Shericka Jackson stepped up for anchor leg duty, the race for the gold medal was already in US hands.

The night before, Richardson might have finished a distant third behind the imperious Jackson in the 200m final, but over half that distance the Jamaican was never going to make up a gap of two metres on the US sprinter who beat her to 100m gold.

Thus it proved, as Richardson charged down the home straight, crossing the line still clear in front in 41.03 – an improvement of 0.04 on the championship record set by Jamaica in Daegu in 2011.

Jackson brought the Jamaicans home 0.18 behind, in 42.21, with the British quartet of Asha Philip, Imani Lansiquot, Bianca Williams and Daryll Neita claiming bronze in 41.97 – ahead of Italy (fourth in 42.49), Poland (fifth in 42.66) and Germany (sixth in 42.96).

On reflection, as Richardson and her teammates celebrated the retention of the title USA gained ahead of Jamaica in Oregon last year, it was their third leg runner who played the decisive role.

At the halfway stage the US quartet was playing catch up, Shelly-Ann Fraser-Pryce having rocketed Jamaica in front with a storming second leg. Up stepped Gabby Thomas – runner up to Jackson in the 200m final but a bend runner supreme.

The graduate of Harvard University, whose list of alumni also includes John Fitzgerald Kennedy and Barack Obama, produced a presidential performance, furnishing Richardson with a lead she was never likely to relinquish.

For Thomas and Richardson, who were backed up on the opening two legs by Tamari Davis and Twanisha Terry, it has been a highly productive first World Championships. Silver and gold for Thomas; two golds and a bronze for Richardson.

The consolation for Fraser-Pryce and for Jackson, who were supported by Natasha Morrison on the lead-off leg and Shashalee Forbes on leg three, was another silver to add to their considerable medal collections from the World Championships.

Fraser-Pryce now has 16 of them, four shy of the record tally held by Allyson Felix: 10 gold, five silver and one bronze.

Jackson, 29, now has 11 medals: four gold, four silver and three bronze.