Shaunae Miller of the Bahamas has won gold in the women’s 400m final after desperately diving across the finish line on Monday night.

She pipped Allyson Felix from the United States, who mounted a surge in the final 200m to finish neck-and-neck with Ms Miller.

But Ms Miller, 22, leapt for a extraordinary climax to complete the single lap race in 49.44 seconds — 0.41 seconds faster than the American —for a personal best.

Bahamas’ Shaunae Miller photo finish dive across the line Alllyson Felix. Photo: Getty

The photo finish, which is measured by the position of racer’s torso, showed Ms Miller diving body crossed the line before Ms Felix’s outstretched leg.

Ms Miller was the silver medallist behind Ms Felix at last year’s world championships in Beijing.

She won the race from lane seven continuing the trend of outside lanes providing surprising results.

The night prior, South Africa’s Wade van Niekerk broke the world record from lane eight in the men’s 400m final.

Ms Felix was widely considered the favourite to win the event.