Usain Bolt admitted he will have little chance of winning another world championship title unless he sorts out his lethargic start after storming to victory at the London Diamond League on Friday.

The Jamaican star also insisted "there was still room for improvement," despite returning to somewhere near his explosive best when winning the 100m at the Olympic Stadium.

The fastest man on the planet - and athletics' greatest entertainer - gave his rivals a decent start before he produced a show-stopping performance as he dashed to victory in 9.85sec, a season's best.

It is not the first time the Olympic champion and world record holder has been tardy out of the traps and not the first time he has managed to show the speed and power to burst through the field and take the tape in front.

Bolt returned to the scene of his heroics in London 2012 and the 60,000 Olympic Stadium crowd roared him on as he beat Michael Rodgers of the US (9.98) and compatriot Nesta Carter (9.99).

Afterwards, Bolt did a victory lap in front of the frenzied crowd, knelt down to kiss the track in his tradition style and then threw his spikes to a lucky fan before departing.

But Bolt admits he needs to put things right quickly before taking his place in the world championships in Moscow next month.

"If I start like that in the world championships I will probably finish fifth." he said.

"I need to work with my coach and figure out how to be more explosive out of the blocks and not so slow," said Bolt.

"But my coach tells me I am not a good starter anyway and to just focus on my running. I know what mistakes I made in the last world championships and executed the start very well in the Olympics.

"I am not worried because my mindset is always different and better come major championships.

"Maybe I will be back to my fastest and best by Moscow."

Asked whether he will return to London to run again, Bolt, who only agreed to take his appearance fee when a tax deal was agreed with the British government, joked: "That depends on the tax situation.

"No, I love coming here. The fans give you so much energy as they did for me a year ago and this is what makes me run faster.

"I felt good tonight and I am pleased with the time I did, even if I was a little slow off the blocks and I had to play catch up.

"There is a lot of room for improvement. I am getting there ... and Moscow is going to be great."

(China Daily 07/28/2013 page7)