The only finalist from the 2016 Games to return was fifth-place finisher Townley Haas of the United States, who did not make the final this time.

[3] Great Britain's Tom Dean put up a monumental effort for the Olympic mid-distance freestyle title in a race against his compatriot Duncan Scott.

Swimming beside the early-leader in Korea's Hwang Sun-woo, Dean was second at the 50 m metre mark before falling to third at the last turn with Scott fifth.

In lane 1, Romania's 16-year old David Popovici charged in the final lap though he could not reel in Scheffer, missing the podium by 0.02 seconds to come fourth.

Up to two swimmers per National Olympic Committee (NOC) could automatically qualify by swimming that time at an approved qualification event.

Up to one swimmer per NOC meeting that time was eligible for selection, allocated by world ranking until the maximum quota for all swimming events is reached.