Michael Phelps helps the United States to gold in his final competitive swimming outing.
The United States have won the gold medal in the men's 4x100m medley relay in Michael Phelps's last competitive swim.
Matt Grevers put the Americans into an early lead during the backstroke leg, but they faced stiff competition from Japan and Australia.
Kosuke Kitajima put to Japan into the lead after the breaststroke stretch, but Phelps put the US back in front after a strong butterfly shift.
Nathan Adrian powered through his freestyle to put the result beyond doubt, hitting the side at 3:29.35, leaving the Japanese with silver.
Team GB did themselves proud, remaining in contention for the podium throughout. They came in fourth when James Magnussen of Australia touched out Adam Brown to clinch bronze.
The United States claimed gold in the women's event earlier this evening.
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