Caeleb Dressel won his ninth career Olympic gold medal from the sidelines as the United States romped to victory in the mixed 4x100m medley relay in world record time at the Paris Olympics on Saturday.

China took the silver and Australia the bronze. France, with Leon Marchand swimming the second leg, finished fourth — the four-gold hero's first defeat in a final at the La Defense Arena.

The winning time of three minutes 37.43 seconds smashed the record of 3:37.58 set by previous champions Great Britain at the Tokyo Games.

Ryan Murphy swam the opening leg for the United States, with Nic Fink and Gretchen Walsh following before Torri Huske made sure of the gold.

Regan Smith, Charlie Swanson, Dressel and Abbey Weitzeil had all swum in the preliminary on Friday to secure the place in the final and were also rewarded for their efforts.

Dressel has only ever won gold medals from his three Games, adding two in Paris to the five he won at Tokyo 2020 and a pair at Rio de Janeiro 2016.

The presence of Marchand, the Paris poster boy whose heroics have brought an unforgettable atmosphere to the converted rugby stadium, raised the roof again. But even the 22-year-old could not work the kind of miracle that was needed.

China's silver medal time of 3:37.55 was also inside the 2021 world record while Australia clocked an Oceanian record of 3:38.76.

Great Britain, without breaststroke powerhouse Adam Peaty, finished only seventh.