Phelps wins 20th and 21st gold medals

Michael Phelps notched up his Olympic gold medal total to 21 on day four of Rio 2016.

The American won the 200m butterfly, before he helped the US win the men's 4x200m freestyle relay.

The swimming superstar has won so many medals that he is the most successful Olympian of all time.

"That's a lot of medals," said Phelps. "It's just insane. It's mind-blowing."

Phelps' win in the 200m butterfly avenged his London 2012 loss to Chad le Clos, who finished fourth this time.

"I wanted that one back. I came into the pool tonight with a mission and the mission was accomplished," added Phelps.

The American will also be trying to add to his gold tally when he goes in the 4x100m medley relay and 200m individual medley, later this week.

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