Faith Kipyegon, the 2015 World runner-up, was the form athlete before the Olympics, being unbeaten and owning the two fastest times for the season – a Kenyan record of 3:56.41 minutes.

Other top entrants included Ethiopians Dawit Seyaum and Besu Sado, Dutch athlete Sifan Hassan, and American former world medallists Jennifer Simpson, Brenda Martinez and Shannon Rowbury.

Shannon Rowbury was relegated to the unwanted leader duties until Laura Weightman moved forward near the end of the lap.

After the slow first lap, even Muir tired of jogging at the back and moved forward, but not Dibaba and Hassan.

Over the next 100 metres, Dibaba cruised to the front, with each of the key figures in the race recognizing she had passed and scrambling to follow.

With a lap and a half to go, Muir was tight on Dibaba's shoulder, followed by Faith Kipyegon, Besu Sado, Jennifer Simpson, Hassan and Rowbury.