[1] U.S. swimmer Dana Vollmer demolished a new world record to clear a 56-second barrier and to claim the Olympic title in the event for the first time since Amy Van Dyken did so in 1996.

[2][3] China's Lu Ying came from behind with the same tactic to grab a silver in 56.87, while Australia's Alicia Coutts nearly pulled from worst-to-podium effort after turning last at the 50-metre lap to put up a late resistant surge for the bronze in 56.94.

Denmark's Jeanette Ottesen Gray paid for an aggressive strategy with an early lead on the first half, before fading to sixth in 57.35.

[6][7] Earlier in the prelims, Vollmer posted both a textile and an American best of 56.25 to lead all swimmers for the top seed, wiping out Inge de Bruijn's 2000 Olympic record by 36-hundredths of a second.

[8] Notable swimmers missed the final roster including Singapore's Tao Li, who delivered a surprise fifth-place finish in Beijing four years earlier; Gandy's home teammate Francesca Halsall; Poland's four-time Olympian Otylia Jędrzejczak; Australia's defending bronze medalist Jessicah Schipper; and Netherlands' Inge Dekker, who later scratched the semifinals to focus on her 4×100 m freestyle relay duty.