In the 4 x 100m medley relay, the United States sent Michael Phelps out on a high note, decimating the field on the final leg to take gold in the last Olympic event of Phelps' storied Olympic career.

The US team was primed for success, featuring three individual gold medalists in their respective legs of the relay (Matt Grevers: backstroke, Nathan Adrian: freestyle, Phelps: butterfly) and the breaststroke bronze medalist Brendan Hansen.

They took the lead straight away in the backstroke, but fell slightly behind after the breaststroke leg of the race to Japan, who kept it very close through two and a half legs of the race. Phelps entered the pool next for the Americans, and blew the competition out of the water.

He provided enough of a cushion as it was, but Adrian used his freestyle prowess to turn it into a blowout win for the USA. The win gave Phelps his 18th gold medal, twice as many as any other Olympic athlete in any sport in the history of the Games.