Michael Phelps hailed after record-breaking Olympic success
Michael Phelps has described his record-breaking achievement at the Olympic Games in Rio as "mind-blowing".
The 31-year-old American swimmer cruised to claim his 21st Olympic gold medal overall after beating defending champion Chad le Clos in the men's 200m butterfly, before adding to his tally in the men's 4x200m freestyle relay later on Tuesday evening.
Speaking to the BBC afterwards, he said: "That's a lot of medals. It's just insane. It's mind-blowing".
By winning the 200m butterfly, he became not only the oldest male swimmer to win an individual gold medal, but also the first man to win the same event in four successive Olympic Games - his last defeat came at the Sydney Olympics in 2000.
Phelps is the most decorated Olympian in history with 21 golds, two silvers and two bronze medals - seven more than the second-highest athlete on the list, Soviet gymnast Larisa Latynina.
He could add to that list in the men's 100m butterfly and 200m individual medley later in the week.
As well as his record-breaking medal tally, Phelps also has six world-records to his name:
Butterfly
100m: 49.82
200m: 1:51.51
Medley
400m: 4:03.84
4x100m: 3:27.28
Freestyle
4x200m: 6:58.55
4x100m: 3:08.24
The US Olympic team were among the first to pay tribute and posted an image on twitter marking Phelps' milestone.
US basketball star Kevin Durant celebrated with Phelps as well as Katie Ledecky, who won gold in the women's 200m freestyle on the same evening.
Former Australian swimmer Ian Thorpe also passed on his congratulations, as well as American actor David Hasselhoff.
Michael Phelps has won 25 medals in five Olympic Games (he failed to win any in his first Olympics in Sydney, 2000).
Here is a breakdown of his medal tally: