The much-hyped head-to-head race between US swimmer Michael Phelps and a Great White shark turned out to be a computer simulation, drawing complaints from many disappointed viewers, reported BBC.

The world's most decorated Olympiad completed the 100m distance in open ocean off South Africa in 38.1 seconds to the shark's 36.1.

Discovery Channel aired the "race".

But what viewers actually saw was a montage of Phelps swimming alongside a computer-generated Great White.

Before Sunday's broadcast, Discovery had the 28-time Olympic medallist, who is now retired, and the shark swim the course separately.

Computer-generated footage of a shark was then superimposed over the swimmer to look like they were racing alongside each other.

Some social media users loved the "race" idea, but many said that they felt "robbed" by the simulation.

source: BBC

Although the US athlete represents the peak of human athletic prowess, he can only swim at a top speed of 5-6mph (8-10km/h) without a monofin, while a Great White is capable of doing at least 25mph in short bursts.

But humans have long pitted themselves against dangerous animals, often ones they know are much faster.

They have done this for money; to draw attention to a cause; to create a spectacle, and perhaps also out of an inflated sense of what humans are capable of.