Usain Bolt will not let his "horrifying" farewell run in Jamaica undermine his confidence going into the World Championships as he seeks to sign off a stellar career in style.

The eight-time Olympic champion reminded his rivals that he remains the fastest man in the world, despite an underwhelming 10.03 seconds over 100 metres on home soil this month.

In the meantime Andre De Grasse - who took third in the 100m in Rio and silver in the 200m - clocked a wind-assisted 9.69secs in Stockholm to underline his growing threat to Bolt's supremacy, and long-time rival Justin Gatlin won the US trials last week.

But Bolt, who will compete in Wednesday's Golden Spike meeting in Ostrava, was defiant when asked if he would be able to keep up with the competition in his final outing on the global stage in August.

"I am the fastest man in the world so I will say yes to that," he said, before playing down De Grasse's time in hugely beneficial conditions. 

"Every time I hear a wind-assisted time my friend NJ [Nugent Walker, Bolt's executive manager] always calls me and says: 'Why are we never this lucky?' We always have negative wind.

"The possibility with a strong tailwind is endless. We have always thought about it. I have never been that lucky."

The 30-year-old admitted that anxiety got the better of him on an emotional night in Jamaica, when thousands turned out to see him run in his homeland for the final time - his modest time still enough for a fitting victory.

"I always get nervous for my first race, but I was really nervous just with the energy and the amount of people there," he said.

"The only time I have seen the stadium full like that was the girls and boys' champs so it was emotional to come out and be there in front of my parents and best friends, it was something different.

"Race-wise it was horrifying. It was really bad. I didn't feel smooth as I should have. Bad start. Everything was just not perfect. But over time I will feel good and get better. And I think with running two more races for the championships [in Ostrava and Monaco] I will be fine."