Michael Phelps rounded off his record-breaking Olympic career on Saturday with a 23rd gold medal, helping the United States' 4x100 metre medley relay team to victory in the final swimming race of Rio 2016.
Phelps, who insists he will not compete in the Tokyo Games in four years, has enjoyed a superb Olympics in Rio, adding five golds to his astonishing haul.
The 31-year-old American had to settle for silver in Friday's 100m butterfly as Singapore's Joseph Schooling produced a dominant performance.
Yet Phelps was back on top of the podium 24 hours later, alongside Ryan Murphy, Cody Miller and Nathan Adrian, after playing his part in a 4x100m medley relay victory for the fourth successive Games.
Murphy's time over the first 100m - 51.85 seconds - saw him break the world backstroke record.
Great Britain finished 1.29 seconds behind USA - who set a new Olympic record of three minutes and 27.95 seconds - to take silver, with Australia taking the bronze.
USA also claimed a landmark victory in the women's 4x100m medley relay, success for Kathleen Baker, Lilly King, Dana Vollmer and Simone Manuel securing the country's 1,000th Olympic gold medal.
Pernille Blume of Denmark claimed a breakthrough victory in the women's 50m freestyle, edging out 100m champion Manuel and Aliaksandra Herasimenia in a tight race as the 2012 victor, Ranomi Kromowidjojo, finished outside the medals.
Italy's Gregorio Paltrinieri produced a stunning front-running display to win the men's 1500m in a time of 14:34.57, ahead of Connor Jaeger and Gabriele Detti.
RACE OF THE DAY
The women's 50m free predictably provided the tightest finish of the day, Blume finishing just two hundredths of a second ahead of Manuel. Kromowidjojo was only 0.12secs back in sixth.
USA's winning time in the men's 4x100m medley relay shaved more than a second off their previous Olympic record - set in 2008 - and was only marginally outside their world record of 2009. Murphy played a key role en route to his third gold of the Games, taking nine hundredths off Aaron Peirsol's backstroke world record.
QUOTE OF THE DAY
"I tried to go out faster and put out a gap between me and the others. It was tough. After 1000 metres or 1100 metres I was really dead but I am very happy about this performance. It's amazing," - Paltrinieri pushed himself to the limit to take 1500m gold.