RIO DE JANEIRO (AFP) - 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.

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 1min 55.28sec.

Francine Niyonsaba of Burundi took silver in 1:56.49 with Kenya's Margaret Wambui claiming bronze in 1:56.89.