Caster Semenya breezed into the semi-finals of the 800m by winning her heat in 1:59.31.
The South African, who found herself at the centre of a gender row following her victory at the 2009 World Championships and had to undergo gender testing before being cleared to return to competition, is the red hot favourite for gold in Rio.
The 25-year-old has been cleared to run as a woman by a Court of Arbitration for Sport ruling, but the controversy surrounding her eligibility remains.
CAS suspended the rules of athletics’ world governing body the IAAF on ‘hyperandrogenism’, which causes unnaturally high levels of testosterone, in a case last July, meaning athletes on testosterone-suppressing medication, like Semenya, could come off it.
Semenya’s body produces three times as much testosterone compared to the normal level found in women.
In London 2012, Semenya took the silver medal in the 800m but was taking medication to lower testosterone levels.
Semenya never complained, but India’s Dutee Chand, another athlete with hyperandrogenism, did.
In 2015, the Court of Arbitration of Sport overturned the ruling by the IAAF, meaning athletes such as Chand and Semenya no longer had to take testosterone-suppressing medication.
Earlier this year Semenya ran the fastest time in the world since 2008, 1:55.33, and looks capable of challenging Czech Jarmila Kratochvilova’s 33-year-old world record of 1:53.28.
Lynsey Sharp joined Semenya in qualifying for the semi-finals, finishing well to win her heat in 2:00.83, while Shelayna Oskan-Clarke went through as a fastest loser after a third-placed finish in 1:59.67.

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