Lennox Lewis has said that it only takes one punch for Dereck Chisora to upset the odds against Vitali Klitschko.
Chisora challenges the Ukrainian for his WBC heavyweight title at the Olympiahalle in Munich on February 18.
The Londoner has lost two of his last three bouts, but former undisputed champion Lewis does not believe that the result is a foregone conclusion.
"Vitali is very good but Chisora has a chance," said the 46-year-old.
"He is a heavyweight. All it takes is one punch on the chin to win. I always say if you walk into the ring you have to get wet.
"If [Klitschko] is in the fight, in the ring, and he gets punched, there is a chance that he might get hurt or knocked out. It will be an interesting fight."
Lewis was the last man to beat Klitschko when the two met at the Staples Centre in Los Angeles in 2003.
