Asafa Powell believes he is ready to make fools of the critics who have tried to bury his career by branding him a choker and the lost man of world sprinting.

Jamaica's former world record holder, the star attraction of tonight's programme in the two-day Aviva London Grand Prix, not only vows to reclaim his 100m landmark from compatriot Usain Bolt but is confident that he is still the man to beat for gold in Beijing.

The 25-year-old has endured a difficult year; struggling with injuries, losing his world 100m record to Bolt and finding himself increasingly saddled with the reputation, following his stuttering bronze-medal finish in the world championship final behind Tyson Gay, of failing to deliver on the biggest occasion.

Yet after fearing that he might miss the Games because of the shoulder injury which delayed the start of his season, Powell looked back to his best after his 100m victory over Bolt in Stockholm on Wednesday in a searing 9.88sec.

"I'm the only one who can defeat myself," he declared. "I was very concerned. With the shoulder injury, I thought my Olympics were over but my confidence came back as soon as I started training again. I still think I'm capable of doing anything I want.

"People are making like 'Asafa is dead, Asafa cannot ran fast again' but I can run faster than I did the last time," added the man who saw his second 100m world record of 9.74sec, set in Rieti last September, eclipsed by Bolt's 9.72sec run in New York in May.

The laid-back Powell sounded so unusually bullish that he even had a taunt for American world champion Tyson Gay, who was due to race him tonight but withdrew, citing a hamstring injury he picked up during the US trials.

"If you know someone is better than you, hiding from them won't make it better," said Powell. "Tyson's only beaten me once in his life so it doesn't make any difference to me."

That 'once', however, was the world championship final, during which Powell seemed to become nearly paralysed with tension.

In Gay's absence tonight, Powell will be pushed by a trio who have all run sub-10sec this season - Trinidad's Richard Thompson (9.93sec), American Travis Padgett (9.89sec) and Jamaican Nesta Carter (9.98sec) - plus Olympic 200m champ Shawn Crawford.

With a warm, still evening expected, Powell is not ruling out the prospect of bettering Bolt's record. "Of course it's possible but I've never once gone onto a track thinking about a world record, so I always surprise myself when I do it," he said.

But the best bet, as ever, to pick up one of the 50,000 dollar world record bonuses is Russian pole vault queen Yelena Isinbayeva.

Back at the stadium where she's won for the last five years, setting three world records in the process, the women's equivalent of Sergey Bubka will be after a 23rd global record here, having set a new landmark of 5.03m in Rome two weeks ago.

Isinbayeva is one of just 36 world champions who'll be on view over the two days, plus all the British medal contenders in Beijing, from Phillips Idowu, in tonight's triple jump, to heptathlete Kelly Sotherton, who will warming up with a 'four-event challenge', contesting the long jump and 100m hurdles tonight and the shot and 200m tomorrow.

New British women's 100m record holder Montell Douglas will be able to test her credentials against world No1 Torri Edwards, of the United States, and Jamaica's world champion Veronica Campbell - which will prove a very tough challenge.

Andy Baddeley will also get the chance to gauge how realistic his 1500m hopes are when he attempts to add victory in the Emsley Carr mile to the Dream Mile he won in Oslo.

If he wants to add his name to Roger Bannister and Seb Coe on the roll of honour, though, he will have his work seriously cut out against Beijing favourite, Bernard Lagat.