According to T&FN, Hayes's mark is the third fastest in world history. It's the second straight year that the American record in the event has gone down after Hastings broke Allyson Felix's mark last year. Today was the first meet on Clemson's newly banked track.
Hayes excelled indoors last year as well, winning an indoor national title and a world indoor bronze medal in the 400 meters as well as a 4x400m gold at world indoors. She was eighth in the 400m final at the Olympic Trials.