Michael Phelps (Getty Images)
Cape Town - Michael Phelps proved without a shadow of a doubt he's the greatest ever Olympian with an incredible 20th gold medal in Rio.
Phelps repelled the threats of defending champion Chad le Clos and Hungarian duo Tamás Kenderesi and László Cseh in a stunning swim in the 200m butterfly on Tuesday night (Wednesday morning in SA).
Phelps led early and wasn't to be denied as he held off surprise silver medallist, Japan's Masato Sakai by 0.04.
Phelps finished in 1:53:36 with Kenderesi taking bronze in 1:53:62.
In a stunning upset, Le Clos failed to medal, finishing fourth in 1:54:06.
The gold was Phelps' second in Rio having earlier been part of the USA's 4x100m freestyle relay winning team.