In her heat and semi-final Packer finished fifth and third, running 2:12.6 and 2:06.0 respectively, being beaten by French runner Maryvonne Dupureur, clocking 2:04.5 and 2:04.1. She thus started the final the second slowest of the eight contestants, having raced at the distance only seven times before. Packer was sixth at 400 m, lying behind Dupureur. She began her sprint to the finish with about 150 m to go, moved up to third at 100 m and took the lead in the final straight, using her sprinting speed to take the gold. She broke the world record with a time of 2:01.1 minutes. Commenting on her win, Packer said "Middle-distance running for women was still in its infancy and the 800 m had only been run in Rome four years earlier for the first time. I knew nothing about the event but being so naive was probably to my advantage; it meant I did not have any limitations in my head regarding what I should or could do. Ignorance proved to be bliss." Packer's winning performance is featured in Tokyo Olympiad the official documentary of the games directed by Kon Ichikawa.