[1] Aaron Peirsol established a new world record of 52.54 to defend his Olympic title in the event.

His teammate Matt Grevers earned a silver in 53.11, giving the United States a one-two finish.

[2][3] Meanwhile, Australia's Hayden Stoeckel and Russia's Arkady Vyatchanin, who both finished behind Grevers by 0.07 of a second, tied for the bronze medal in a matching time of 53.18.

[4] Stoeckel's teammate Ashley Delaney finished fifth in 53.31, while Great Britain's Liam Tancock, who led a field in the first 50 metres, faded only to sixth place in 53.39.

[5] Spain's Aschwin Wildeboer (53.51) and Japan's Junichi Miyashita (53.99) rounded out the finale.