Shaunae Miller (BAH) of Bahamas lies on the track after throwing herself across the finish line to win the gold in the women's 400m final during the 2016 Rio Olympics in Brazil, Aug 15, 2016. [Photo/Agencies]

Silver medallist in the 200m in Athens in 2004 and again in Beijing four years later, Felix won her only individual gold over the half-lap in London in 2012. She has also won three relay golds and could add to that tally in Brazil.

Second behind Felix in the 400 metres at the world championships in Beijing last year when her strong finish was not enough to rein in the American, Miller had clearly learned her lesson.

She exploded out of the blocks in lane seven and went for broke, her long stride giving her a good lead on the back straight as the shorter Felix powered away inside her.