LONDON (AFP) - Olympic champion and world record holder Usain Bolt insists he is still king of the sprinters after returning from injury with back-to-back 100m times of 9.87sec at the London Diamond League meeting.

Asked if his winning performances - in the heats and final on a rain-soaked Olympic Stadium track - proved that he was still the world's number one, the 28-year-old Jamaican replied defiantly: "I was never number two."

"I am still number one. I will continue being number one. Until I retire, that's the plan."

On 100m times recorded in 2015, Bolt is now ranked number six. Justin Gatlin, the American who has served two doping bans, tops the list with 9.74sec and has also run 9.75sec twice and 9.78sec.

Bolt, however, clearly has room for improvement before he defends his 100m and 200m titles at next month's world championships in Beijing on the Bird's Nest track where he won his first trio of Olympic gold medals (100m, 200m and 4x100m relay) in 2008.

The Jamaican has won every global 100m and 200m title contested over the past seven years, with the exception of the 100m at the 2011 world championships in South Korea when he was disqualified for a false start.

It is a period of sprint domination unmatched in the history of track and field, and despite missing six weeks of competitive action following the New York Diamond League meeting because of a pelvic problem, Bolt cannot be discounted from striking gold again.

The fact that he did not get off to the best of starts in his heat and got off to a sluggish one in the final shows that he has room for improvement in the four weeks ahead - as does the fact that he was running on a rain-soaked track and into a head wind on both occasions.

Asked how fast he thought he could go in Beijing, Bolt replied: "Anything is possible. I thought I would run fast in the final tonight but I got a bad start.

"When I got a bad start, then I kind of lost focus for a minute and lost my form but at the last I got it back. It taught me a lot, these two races."

There have been claims that Bolt has been stopping the clock at 9.7sec on the training track, an assertion he declined to dismiss.

"I have been running fast," he said. "I can't say I haven't been running fast in training.

"It is easier to run fast in training because you are under no pressure and you just have to work on it."

Having drastically improved on his one previous 100m time of the year - 10.12sec in Rio de Janeiro in April - Bolt added that his two London performances had set him up nicely for the world championships which begin on August 22.

Reigning 5,000m and 10,000 Olympic champion Mo Farah is an admirer of his close friend B olt. Said the 32-year-old Briton: "He is a legend of the sport. We take it for granted what he does. To achieve what he has and to keep winning is incredible.

"When he retires, it is then that we will realise how good he is."