Published: 02:14 BST, 13 August 2016 | Updated: 19:26 BST, 15 August 2016
Team USA's Maya DiRado caused a major upset after winning a shock gold medal in the women's 200m backstroke at the pool in Rio.
Hungary's Katinka Hosszu was hoping for a fourth gold in the pool, but it was not to be and she had to settle for the silver.
Hosszu, known as 'The Iron Lady' had already won the 100m backstroke, the 200m individual medley and the 400m individual medley, but in Friday night's race, she was caught in the final few meters as DiRado beat her by six hundredths of a second. Hilary Caldwell of Canada took bronze.
Maya DiRado celebrates with her gold medal during the women's 200-meter backstroke medals ceremony
Hungary's Katinka Hosszu, United States' Maya DiRado and Canada's Hilary Caldwell pose with their medals after a hard-fought race
United States' Maya Dirado celebrates after winning a surprise gold medal in the women's 200-meter backstroke final
United States' Maya DiRado reacts after winning gold in the women's 200-meter backstroke beating a shocked Katinka Hosszu of Hungary, seen right, by the smallest of margins
Hosszu had led from the start, reacting fastest from the block, but DiRado shadowed her the whole way.
The Hungarian led the American by 0.57 seconds at 100 meters and by 0.48 at the final turn, but DiRado fought back and the two were neck-and-neck as they entered the final 25 metres.
DiRado touched the wall in 2 minutes 5.99 seconds to win by 0.06 seconds.
Dirado wins! The American looked shocked that she had managed to storm back to win
Gold medalist Maya DiRado of USA reacts during the medal ceremony for women's 200m Backstroke
Even after several minutes, during the medal ceremony, DiRado looked in disbelief at her win
Turning to look at the scoreboard, her eyes widened and she clapped her hand to her mouth as if she could not believe the result.
'It's indescribable. That is just pure joy and surprise and excitement,' she said.
DiRado, 23, added to her gold in the 4x200m freestyle relay, silver in the 400m individual medley and bronze in the 200m IM.
DiRado couldn't believe what she had done in her one and only Olympics.
Gold medalist Maya Dirado poses during the round of honour after the medal ceremony
Watching in the stands was Shane Tusup, the controversial husband and coach of Hosszu.
Earlier in the week he made headlines around the world for his wild celebration of his wife’s 400m individual medley win.
His reactions on Friday night were equally as priceless as he went from agony to ecstacy over the course of a few seconds.
By the end of the race he had a broad smile on his face, knowing that his wife had done the best that she could, and perhaps for a moment thinking that she had struck gold.
Shane Tusup, the husband and coach of Hungarian swimmer Katinka Hosszu, has been noticed at the games for his passionate expressions of support
One can only imagine what Tusup must have been thinking at this moment as his wife was only just beaten by a hair's breadth
Go on! Michael Phelps, who was in the pool shortly after DiRado pumps his fist after his compatriot's gold medal
Meanwhile, Anthony Ervin of the United States reclaimed the mantle of fastest man in the water on Friday by taking the Olympic 50 meters freestyle gold medal 16 years after he first won it, and by the slimmest of margins.
France's Florent Manaudou, the defending champion, finished second and just 0.01 seconds behind the 35-year-old veteran, who won in 21.40 seconds.
Nathan Adrian of the United States took the bronze.
Ervin won his first individual gold medal in a dead-heat in the same event with team mate Gary Hall Jr at the 2000 Sydney Games. Both touched out in 21.98 seconds.
United States' Anthony Ervin celebrates after winning the men's 50-meter freestyle final
Ervin, the 35-year-old, is the oldest ever champion in the swimming pool
Sixteen years after winning his first individual gold medal at the Olympics, Anthony Ervin picked up his second with a furious dash from one end of the pool to the other.
Completing a remarkable journey in the blink of an eye, the oldest member of the U.S. swimming team touched first in the 50-meter freestyle, edging the defending Olympic champion, Florent Manaudou of France, by a mere hundredth of a second.
The 35-year-old Ervin won his first gold at the 2000 Sydney Olympics, tying teammate Gary Hall Jr. for the top spot. Then, Ervin walked away from swimming, skipping the next two Olympics while he embarked on a journey to find his purpose in life.
Turns out, it was swimming all along. He returned to make the American team in 2012, but failed to win a medal in London.
Now, improbably, he's back on the top of the podium again.
Anthony Ervin won the same event in Sydney - some 16 years ago!
Simone Manuel, who became the first African-American woman to win an individual Olympic swimming event on Thursday night also managed to qualify for the women's 50m freestyle event which takes place on Saturday.
The women's 50m freestyle semis were delayed for more than half an hour on Friday night after reports that a bus carrying the participants got lost.
United States' Simone Manuel looks at the clock at the end of the women's 50-meters freestyle semifinals. She will be back in the pool again on Saturday evening