The United States repeated as the gold-medal winner in the men's 4x100-meter freestyle relay on Sunday night.
The quartet of Caeleb Dressel, Blake Pieroni, Bowe Becker and Zach Apple stormed to first place in a time of 3:08.97.
Sunday's victory marked the first gold medal of the Tokyo Olympics for Dressel, who could be one of the most decorated athletes over the next two weeks.
The United States beat out Italy and Australia to capture first place. The Americans now have five overall gold medals in Japan and two of them have come from men's swimming.
1. United States (Caeleb Dressel, Blake Pieroni, Bowe Becker, Zach Apple): 3:08.97
2. Italy (Alessandro Miressi, Thomas Ceccon, Lorenzo Zazzeri, Manuel Frigo): 3:10.11
3. Australia (Matthew Temple, Zac Incerti, Alexander Graham, Kyle Chalmers): 3:10.22
4. Canada (Brent Hayden, Joshua Liendo Edwards, Yuri Kisil, Markus Thormeyer): 3:10.82
5. Hungary (Kristof Milak, Szebasztian Szabo, Richard Bohus, Nandor Nemeth): 3:11.06
6. France (Maxime Grousset, Florent Manaudou, Clement Mignon, Mehdy Metella): 3:11.09
7. Russian Olympic Committee (Andrei Minakov, Vladislav Grinev, Vladimir Morozov, Kliment Kolesnikov): 3:12.20
8. Brazil (Bruno Correia, Pedro Spajari, Gabriel Santos, Marcelo Chierighini): 3:13.41
The United States was out in the front of the race for a majority of the 400 meters.
Dressel allowed the Americans to race from the top of the field by turning in a first leg of 47.26 seconds.
Dressel produced the second-best time of the four swimmers on his relay team. The fastest number came from anchor Zach Apple.
Apple stormed through the pool in 46.69 seconds to create some separation between the Americans, Italy and Australia.
The United States entered the final with a qualifying time that was over a second worse than Italy, but the team from the preliminary round did not have Dressel swimming a leg.
Dressel will take part in the 100-meter butterfly, 100-meter freestyle and 50-meter freestyle on an individual level over the next week. He could be involved in medley relays as well.
Italy did not have a swimmer go under 47 seconds, like Apple, but it did have all four competitors turn in times fewer 48 seconds.
The fastest lap in the pool was produced by Australian anchor Kyle Chalmers, who went through the 100 meters in 46.44 seconds.
NBC Sports' Nick Zaccardi pointed out how fast Chalmers' time was and what it means for the men's 100-meter freestyle final.
As Fox Sports Australia pointed out, the Aussies were sixth when Chalmers entered the pool and he brought them back to a bronze medal.
The United States' overall time was a second faster than the gold-winning team from Rio de Janeiro.
Dressel was the only holdover from the unit that swam 3:09.92 to win gold in Rio. Michael Phelps and Nathan Adrian were part of that squad.
The United States now owns five gold medals from four different sports. Sunday's relay win made swimming the first multi-gold sport for the Americans in Tokyo.