Katie Ledecky, who is expected to set or challenge world and Olympic records in all three of her individual events at Rio, did not disappoint on Sunday afternoon.
In her very first individual event, the 400-meter preliminaries, Ledecky flirted with breaking her own world record (3:58.37) before settling for a new Olympic record of 3:58.71.
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France's Camille Muffat, who died in a helicopter crash last year, had set the previous mark 4:01.45 in the 2012 London games.
The 19-year-old Ledecky told NBC after the race she knew the crowd was into her pursuit of the record.