Former world heavyweight champion Lennox Lewis thinks unfancied Brit Dereck Chisora has the power to shock Vitali Klitschko later this month.
Klitschko chose to meet 28-year-old Chisora, instead of another Londoner David Haye, in the defence of his WBC heavyweight title on 18 February.
The 40-year-old Ukrainian was last defeated nine years ago by Lewis.
"Vitali is very good but Chisora has a chance. All it takes is one punch on the chin to win," said Lewis.
Chisora has lost his last two title fights after defeat by Tyson Fury in their battle for the British and Commonwealth belts and a controversial points loss against Robert Helenius in December.
But the Zimbabwe-born fighter insists he can bounce back in style by knocking out Klitschko in Munich.
Lewis stopped Klitschko in the sixth round of their 2003 bout in Los Angeles to retain his WBC and IBO crowns before retiring from the sport.
And he believes Chisora has the punching power to cause a big upset.
"I always say if you walk into the ring, you have to get wet," said the 46-year-old.
"If he [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."
Chisora, whose two scheduled fights against Klitschko's younger brother Wladimir were cancelled, won the race to face Vitali ahead of compatriot Haye.
Haye, 31, has not fought since surrendering his WBA heavyweight title to WBO and IBF champion Wladimir in July 2011.
However, the Bermondsey fighter insists he is ready to come out of retirement and challenge Vitali.
Lewis said: "He should come back, but he should not think about the Klitschkos right now.
"He should beat a couple of other people, so people actually think 'yeah, you know, he can do it this time, he can beat a Klitschko'."