[1] U.S. distance ace Katie Ledecky put together a powerful attack on her existing world record to become the first Olympic champion in the event for the Americans, since Brooke Bennett topped the podium in 2000.

Leading from the start, Ledecky quickly dropped two seconds under a world-record pace, as she pulled away further from the field to smash her own record with a gold-medal time in 3:56.46.

[2][3] Trailing the leader by almost five seconds, Great Britain's distance-freestyle swimmer Jazmin Carlin fought off a tight battle against Ledecky's teammate Leah Smith on the final lap for the silver in 4:01.23.

[5][6] Boglárka Kapás missed the podium in fourth with a Hungarian record of 4:02.37 from the outside lane, while Canada's Brittany MacLean posted a fifth-place time in 4:04.69.

[5] Earlier in the prelims, Ledecky opened her first individual race of the Games with a new Olympic record of 3:58.71 to immediately lock the top seed for the final, clearing a four-minute barrier at the Games for the first time, and slashing 2.74 seconds off the mark set in London 2012 by reigning champion Camille Muffat of France, who was killed on a helicopter crash in March 2015.