Katie Ledecky, already a two-time medalist at these Rio Olympics, won gold in the 200m freestyle in a time of one minute, 53.73 seconds on Tuesday night.
Ledecky represented the Americans' only medal hopes in the event, as Missy Franklin did not advance out of the semifinals.
Ledecky's individual winning streak increased to 14-0; she has never lost a major international final at meets such as the Olympic Games, world championships or Pan American Championships.
"It hurt really badly," Ledecky said to media after the race. "I’m pretty sure that’s the closest I’ve come to throwing up in the middle of a race. I’m just so glad I got my hand on the wall first. It was all worth it."
Sarah Sjostrom of Sweden earned the silver, a quarter of a second behind Ledecky. More on the pair’s much-hyped rivalry here.
Australia’s Emma McKeon took the bronze with a time of 1:54.92.
The world record of 1:52.98, set in 2009 at the height of the rubberized suit era, could not be touched. Federica Pellegrini, who still owns that record, finished fourth.
Ledecky won her two other Rio medals when she took gold in world record time in the 400m freestyle and alongside teammates Dana Vollmer, Simone Manuel and Abbey Weitzeil the 4x100m freestyle relay (silver). She is the runaway favorite in the 800m freestyle as the defending Olympic champion in the event – preliminary heats begin Thursday – and she is expected to be named to the 4x200m freestyle relay team, racing Wednesday.
"The preparation is tremendous, and the preparation that she's done for a long period of time, the preparation includes the training and that means taking care of herself away from the pool, and it includes the visualization of the race and it includes making some adjustments from yesterday... her preparation is top notch," Ledecky's coach, Bruce Gemmell, told media.