Caeleb Dressel collected his eighth career Olympic gold medal when he anchored the US men to a second successive 4x100 metres freestyle title at the Paris Olympics on Saturday.
Australia took silver and Italy the bronze, with China missing out on the medals in fourth place.
Jack Alexy, Chris Giuliano, Hunter Armstrong and Dressel combined in a time of three minutes 09.28 seconds to beat Australia by 1.07 in the last final of a raucous opening night at the La Defense Arena.
Matt King and Ryan Held swam in the morning heats but were switched out in favour of Alexy and Giuliano for the final. King and Held will also receive gold medals.
Dressel won five golds at Tokyo in 2021 and two in Rio de Janeiro in 2016.