KINGSTON, Jamaica — Noted journalist and track and field analyst Leighton Levy says Sunday’s final of the men’s 100-metre event at the IAAF World Championships in Beijing, China will be sprint great Usain Bolt’s biggest test of his career.

Jamaica’s Bolt, whose season’s best is 9.87 seconds will on Sunday take to the Bird’s Nest track — site of his first trio of Olympic Games gold medals (100m, 200m and 4x100m relay) in 2008 — for the semi-finals and expected final of the 100m.

His main rival in Beijing is Justin Gatlin, the American who tops the list of fastest times this year with 9.74 seconds, 9.75 twice and 9.78.

“We are going to have a war in the final and I think it’s going to come down to execution. This is basically the biggest test Usain Bolt will ever face in his career,” Levy told the OBSERVER ONLINE on Saturday.

“Justin Gatlin is running virtually perfect every single time he takes the track. Bolt cannot afford to be less than close to perfect. He needs to be close to perfect to be able to beat Gatlin. If Gatlin gets away from him midway through the race [the acceleration phase], that’s it,” he declared.

Gatlin, 33, was timed fastest in Saturday’s Heats, but his 9.83 seconds was assisted by a wind of 2.1m/s.

Bolt, 29, ran a fairly comfortable 9.96s against a -0.2m/s wind.

For blow-by-blow coverage of the 15th IAAF World Championships from #Beijing2015 follow @ObserverLive.Sanjay Myers