American swimming legend Michael Phelps kept on adding to his gold kitty at the Olympics, taking his tally to 21 after winning gold at the 200 metre butterfly and the 4 x 200 metre freestyle relay events. The most decorated Olympian of all time, Phelps now has 25 total medals in all Olympics.

Having already won gold at the 4 x 100 metre freestyle relay, Phelps was in supreme form in his signature event on Tuesday, the 200 metre butterfly, clocking a time of 1.53.36 to surge to the top spot. In the process, he took some measure of revenge on South Africa's Chad le Clos who had pipped him to gold by five-hundredths of a second in the same event at the 2012 Olympics in London.

Then, Phelps completed the fourth leg of the 4 x 200 metre freestyle relay and complete another comfortable victory, earning himself another gold medal.