Semenya's run puzzled many because she stayed at the back of the pack for much of the race on Saturday before sprinting forward at the last minute but unable to claim the winning place expected of her by so many South Africans - and bookmakers.

An article on US website Slate, and comments on Twitter, have suggested that Semenya came second to avoid the controversy about her gender that dogged her after her win at the 2009 World Championships.

University of the Free State rector Jonathan Jansen tweeted hours before the race: " Provided Caster and Oscar lose, there will be no controversy."

Tweeter Shabbisto Mavuso said: "It looks like if Caster wanted the gold she would have gone for it but decided for the silver for less controversial reporting."

Other South Africans expressed disappointment.

Cosatu secretary-general Zwelinzima Vavi joined in: "Congratulations to Caster on silver medal even though I thought she waited too long at the back before making a move."

Semenya yesterday admitted that she had made a mistake by starting the race too slowly. Her admission had many on twitter asking why the silver medallist had to explain herself.

Thula Sindi tweeted: "I really wish politicians & government ministers were held to account as much as Caster Semenya."

Even writer Salman Rushdie had words of praise for the South African.

He called Usain Bolt and Mo Farah heroes but said Caster Semenya surpassed them.

"Mo, Usain: heroes. But Caster Semenya, coming back from being humiliated in the row over her gender to win silver: an even bigger heroine."

Singer Sibongile Khumalo said South Africans had no right to express disappointment about Semenya's Olympic performance.

"Caster Semenya is an Olympian! Finish and Klaar.

"What are we? Twitterlympians, on our couches with our analyses?

"What courage, boldness!"