In the final, Hennagan again went for the lead with Amertil and Natalya Nazarova each taking their shot at her in the first 200, only to fade after.

Starting slightly slower, Williams came on strongly on the backstretch, marked by Guevara around the second turn.

Hennagan tried to fight, long striding with a slowing cadence to the finish, losing ground to a fast closing Antyukh.

3 meters back, Antyukh clearly beat a wilting Hennagan, who still managed to hold off the fast closing Trotter.

For the men's 400 metres, each National Olympic Committee was permitted to enter up to three athletes that had run the race in 51.50 seconds or faster during the qualification period.