"I'm disappointed. My start was not good enough. That was the key tonight," said the 6-foot-5-inch Bolt.

"I was also disturbed by the false start. I could not focus at 100 per cent," added Bolt, who erased Powell's world mark by 0.02 seconds - with his 9.72 second run at the Reebok Grand Prix in New York in May.

Powell's win avenged his loss to Bolt at the Jamaica Olympic Trials last month in Kingston, and with reigning World Champion Tyson Gay bothered with a hamstring injury, the two Jamaicans are clearly among the top contenders for gold in Beijing.

In the meantime, Bolt remains positive about his build-up for the August 8-24 Olympics, and had a sharp answer to questions about whether his defeat lowers his stocks for Beijing.

"That doesn't change anything," Bolt said.