Usain Bolt says he is "ready to win" at next month's World Championships after securing 100m victory at the Anniversary Games in 9.87 seconds.
American Justin Gatlin has run the four fastest 100m times this year, setting a personal best of 9.74 in May.
But Bolt twice ran under 10 seconds at the Olympic Stadium on Friday to show he is coming back to form after injury.
"I was never number two, I am still number one. Until I retire that's the plan," said the double world champion.
"I was happy with what I did," added the six-time Olympic champion who has struggled with a pelvic problem this year.
"I'm ready to go and I'm ready to win."
With less than a month until the Jamaican defends his 100m and 200m world titles in Beijing, it was a confidence-boosting win for the 28-year-old.
Prior to Friday, Bolt had only once raced over 100m this year - a pedestrian 10.12 in Brazil in April - so there were those who questioned his ability to challenge Gatlin in August.
But he effortlessly won his heat running into a headwind and while winning the final was more of a challenge, he still equalled his season's best - produced in his heat earlier in the evening - which is the equal sixth quickest time of the year.
"Yeah, I had a poor start," said Bolt of the final. "I need to work on that, but overall it was an OK race.
"My coach [Glen Mills] told me about my start. It was bad. I wanted to run faster and it threw me off but I'm getting there."
Gatlin, a two-time drugs cheat, has run under 9.8 four times this year - 9.74, 9.75, 9.75, 9.78 - while Bolt has run just three races in the blue riband event in 2015.
|Olympic medallist Darren Campbell on BBC Radio 5 live|
|"I didn't believe Usain Bolt yesterday when he said he would be at the World Championships in Beijing. I do now.|
|"His run of 9.87 seconds was not perfect - I would say he is in 90% shape.|
|"This performance tonight will give Bolt the confidence that he can go to Beijing and beat Justin Gatlin.|
|"He has a got a month to smooth out that start and first 40m and I think he will do it."|
But the fastest man in history is closer to the heels of Gatlin than many had previously thought.
"I don't fear anyone," he told BBC Radio 5 live sport.
"It's all about hard work and dedication and pushing myself."
The pelvic problem which forced him to withdraw from Diamond League meetings in Paris and Lausanne this month did not hinder him as he ran twice in 80 minutes on the first of a two-day Diamond League meeting in London.
"Anything is possible in Beijing - it's all about the effort you put in," he added. "I've been running fast in training, but it's easier in training because you're under no pressure and you can execute well."
Asked whether he planed to race again before starting the defence of his double sprint world titles on 23 August, Bolt said: "I don't know. It's all up to the coach. He'll tell me if I need more meets."