Audley Harrison says he has no intention of retiring despite losing his second successive fight on Friday.
Harrison won Olympic gold in Sydney
Harrison's points defeat to America's Dominick Guinn in California followed his much-derided loss to fellow Londoner Danny Williams last December.
"I've got to re-galvanise myself," said the 34-year-old Harrison. "I wasn't hurt at all at any time, I just didn't put my foot on the gas.
"I've just got to go back to the drawing board. This ain't over yet."
Harrison, who won gold at the 2000 Olympics, has now lost two of his 21 professional encounters.
But Harrison still believes he has what it takes to become heavyweight champion of the world.
"I've got to keep working on it," said Harrison. "I'm close, but I just haven't come over the mountain yet.
"Frank Bruno went for world titles three or four times and eventually he got there."