South Africa's Caster Semenya cruised to victory in the women's 800m on Saturday, producing a devastating final kick to claim her first Olympic gold medal.
The 25-year-old 2012 silver medallist turned on the gas with 150m to go to cross the line more than 1.20sec clear of the field in 1.55.28sec at the Olympic Stadium.
Francine Niyonsaba of Burundi took silver in 1:56.49 with Kenya's Margaret Wambui claiming bronze in 1:56.89.
Semenya has been at the centre of a raging controversy in recent years because of her naturally occurring condition, hyperandrogenism, which causes elevated testosterone levels. Rival runners have said they want authorities to revisit rules that limit the amount of testosterone allowed in competitors. Semenya exploded onto the global athletics scene in 2009, winning gold at the World Championships in Berlin as an 18-year-old prodigy.