[1] Dutch swimmer Ranomi Kromowidjojo swam to a new Olympic record to become the country's third gold medalist in the event, along with Rie Mastenbroek in 1936 and Inge de Bruijn in 2000.

In fourth place at the halfway turn, she pulled ahead of a tightly packed field to touch the wall first and improve her own record in 53.00.

[2][3] Belarus' Aliaksandra Herasimenia was in the lead on the first length under a world-record pace, but faded down the stretch to win the silver medal in 53.38.

[7] Great Britain's home favorite Francesca Halsall (53.66), Denmark's Jeanette Ottesen (53.75), who shared the title with Herasimenia at the 2011 World Championships, and U.S. swimmer Jessica Hardy (54.02) finished in sixth through eighth place.

Sweden's five-time Olympian Therese Alshammar suffered a pinched nerve in her neck, and skipped most of her events.