[1] As the most decorated Olympian of all time, Michael Phelps continued to ramp up his already astonishing resume with an unprecedented second Olympic three-peat and another title defense.

Rallying from seventh at the halfway turn, he produced a remarkable swim over the rest of the field to claim his seventeenth gold and twenty-first career medal in 51.21.

[4][5] Leading early at the turn, Serbia's Milorad Čavić, who famously lost to Phelps in Beijing four years earlier by a fingertip, faded down the stretch to match Germany's Steffen Deibler with a fourth-place time in 51.81.

[6] Netherlands' Joeri Verlinden (51.82), U.S. swimmer Tyler McGill (51.88), and Poland's Konrad Czerniak (52.05) also vied for an Olympic medal to round out a historic finish.

[5] Austria's Dinko Jukic (51.99), fourth-place finalist in the 200 m butterfly few days earlier; and Kenya's Jason Dunford (52.16), fifth in Beijing, missed the final roster after placing ninth and sixteenth respectively in the semifinals.