Former undisputed heavyweight world champion Lennox Lewis believes Carl Froch will have his work cut out if he fights American Andre Ward.
Froch defended his IBF super-middleweight title and took Mikkel Kessler's WBA belt with a unanimous points decision win over the Dane at London's 02 Arena.
A previous defeat to Kessler and one to Ward are the only blemishes on Froch's professional career but Lewis thinks the Nottingham boxer should be wary of the American.
Lewis told BBC Radio 5 Live's Sportsweek programme of the prospect of Froch fighting Ward: "He's really going to have to go to camp and fix up some of his technical issues.
"He cannot fight the same way he fought in this fight.
"Against Andre Ward he has got to be a little bit scared because Andre Ward is a serious hombre and he's coming there to fight and he's looking for that knockout.
"If he sees a chink in your armour in any way he will seize that opportunity."
Lewis was impressed with the way Froch stepped up and took the fight to Kessler.
"Let me tell you he felt really comfortable in there," Lewis added.
"He basically threw a lot of the boxing out of the door and he was just going in there for a smash-up. He boxed really well, he was in control."
Kessler rocked Froch with a punch in the sixth round and that was an area of concern for Lewis.
"There were a couple of sticky moments that I was concerned about but he did very well. He showed he can take a punch.
"I was surprised at Kessler because although he looked like the better boxer he just didn't have the heart for it.
"Froch had the heart and the willingness. He just wanted to show everybody that he's a banger.
"He really dug deep. Even that last round because if I was his trainer I would have told him he had won the fight and he did not need to risk anything.
"But he wanted to risk it and he wanted to go in there and knock Kessler out."