MICHAEL Phelps became the most decorated Olympian of all time after winning his 19th medal with a gold in the men's 4x200 metres freestyle final at the Aquatics Centre in London.
Phelps helped United States to a comfortable victory in 6:59.70, giving him his 15th gold to add to his two silver and two bronze medals.
One of those silvers came earlier in the morning (AEST) when he finished runner-up to South Africa's Chad Le Clos in the 200m butterfly final.
Australia was fifth in the 4x200m freestyle final in 7:07.00.
Four years after he climbed to the top of Olympic achievement, Phelps took the last step he needed to reach the absolute peak.
Michael Phelps: The Greatest Olympian
Gold: 100m/200m butterfly, 200m/400m individual medley, 4x200m freestyle relay, 4x100m medley relay
Bronze: 200m freestyle, 4x100m freestyle relay
Gold: 200m freestyle, 100m butterfly, 200m butterfly, 200m/400m individual medley, 4x100m freestyle relay, 4x200m freestyle relay, 4x100m medley relay
Gold: 4x200m freestyle relay
Silver: 4x100m freestyle relay, 200m fly