Perhaps it had to happen at some point, but it was still shocking when it did. Michael Phelps's winning streak at Rio 2016 came to a surprise end on Friday (12 August) night, when 21-year-old Joseph Schooling won Singapore's first Olympic gold medal with victory in the 100m butterfly.

Phelps, who had already won four golds in Rio, was one of three men to finish joint second: Chad Le Clos, Laszlo Cseh and Phelps shared the silver medal.

Social media caught fire after the resullt, with old photos posted of Schooling together with Phelps when the younger man was a boy.

Schooling was in a state of disbelief when he spoke to reporters soon afterwards. "I'm sorry if I don't seem like I'm full of emotions but I don't know what to believe - that I actually did it or I'm still preparing for my race," he said. "I'm between the two of them."

Schooling leads, with Le Clos chasing (Photo: Getty Images)

"I need to let this moment sink in, realise what I've done and then I'll have a better understanding of what I accomplished," Scololing said. "But right now all I can say is I'm really honoured and privileged to have an opportunity to race in an Olympic final alongside huge names like Michael (Phelps), Chad (Le Clos), and Laszlo (Cseh), guys that have redefined the sport."

Schooling said Phelps shared some words after the race. "He said, 'Good job, that was a great race'. I told him, 'Four more years?' and he said, 'No way.' If he changes his mind, that would be fun. I like racing Michael."

After looking unbeatable in Brazil, Phelps finally ran out of steam in what was the final individual race of his career unless he decides to come out of retirement again.

Phelps still has a chance to leave Rio with 23 golds in his career. But he'll have to do with some help from his team-mates, swimming in the butterfly leg of the 4x100m medley relay on the final night of swimming on Saturday.

Phelps settled for silver along with two longtime rivals, Le Clos of South Africa and Laszlo of Hungary. They all touched in 51.14 – a half-body length behind Schooling's winning time of 50.39.

When is Michael Phelps racing at Rio 2016? What time is he swimming at the Olympic Aquatics Stadium?

"A three-way tie is pretty wild,"said Phelps. "It's faster than I went, I think, four years ago to win. Joe (Schooling) is tough. He had a great year last year and has had a really great last two years so hats off to him. He swam a great race."

While Phelps' loss left the crowd in shock, Katie Ledecky restored some normalcy with another dominating performance that saw her break the world record in the 800m freestyle.

Ledecky joined Debbie Meyer as the only women to sweep the three longer freestyle events at the same Olympic Games. Meyer took the 200m, 400m and 800m at the 1968 Mexico Games, and Ledecky matched that performance with a couple of world records as well.

Ledecky, Peaty, Phelps and Sjostrom shine on incredible night at Olympic Aquatics Centre

Ledecky was merely racing the clock as she powered away from the field to touch in eight minutes, 4.79 seconds, eclipsing the mark 8:06.68 that she set at a grand prix meet in Texas back in January.

Jazz Karlin finally touched in 8:16.17 to claim the silver, just ahead of Hungary's Boglarka Kapas in 8:16.37.

Swimming at Rio 2016: schedule and results