LONDON, England (BBC) – Usain Bolt is hopeful of adding the 100-metre World Championships title to the Olympic gold medal he won in Beijing last year, despite not being 100% fit.

The 22-year-old warms up for the Berlin event by taking on Jamaican compatriot Asafa Powell over 100-metre at the London Grand Prix at Crystal Palace on Friday.

He told BBC Sport: “Last year I was 100% fit and I did wonderful things, beating the pack by a good distance.

“I’m not sure I will be 100% in Berlin, but if I’m 95% I’ll be in contention.”

Bolt, who is also targeting lowering his own 100-metre world record of 9.69 seconds, which he set at the 2008 Beijing Olympics, is still producing decent times despite not being in top form.

He won the 100-metre at Friday’s Golden League meeting in Paris in a stunning time of 9.79 seconds, despite a poor start.

“I still have a few things to get right, but if I can get everything together I should be ready for the Worlds,” he added.

“I’m looking forward to racing in London because I’m based here and there will be lots of Jamaican support. The fans will be loud and fun and I can feed off their energy.”

Bolt starts Friday’s race as favourite, but Commonwealth 100-metre champion Powell is unbeaten over the distance at Crystal Palace having run under 10 seconds in his previous three races at the venue.

America’s double world champion Tyson Gay, who has run the quickest 100-metre of the year at 9.77 seconds, is also at the London meet, but he runs over 200-metre on Saturday.