A photograph snapped by an Australian is being heralded as one of the greatest ever taken of Jamaican sports star Usain Bolt .

The image captures the incredible moment Usain Bolt qualified for the men's 100 metres at the Rio Olympics with such apparent ease he had time to crack a grin.

The 29-year-old superstar streaked across the line of his semi-final with a cheeky mid-race smile at his rivals.  About 60 metres into the race, Bolt had started glancing from side to side before easing over the finishing line.

A photo of Bolt looking over his left shoulder at Canadian sprinter Andre De Grasse, who appeared considerably less relaxed, was being shared widely on social media, where some suggested Bolt was simply "jogging".

But it was a photo by Getty Images' Cameron Spencer that was rapidly being shared around the world on Monday and attracting the praise of US commentators as capturing "the essence of Bolt so perfectly", and "pretty much Bolt's whole career in one photo".

Bolt posted a time of 9.86 seconds in the semi-final, and was in complete control of the race from the start. 

It set up a final showdown with American Justin Gatlin, who also controlled his semi-final, clocking 9.94.

Bolt then went on to demolish the field in the final, winning his third consecutive Olympic gold medal in the 100 metres with a time of 9.81 seconds.

The win took the sprinter a step closer to his goal of winning a historic "triple-triple" combination -  of gold in the 100m, 200m and the 4x100m relay in three consecutive Olympics.

American Justin Gatlin won silver in 9.89 and Canada's Andre de Grasse bronze in 9.91. 

Courtesy SMH