"After the first leg, it's difficult to say Celtic have any hope of getting the result they need in Turin," he told SunSport.
"If you are honest, thinking as a neutral and not a Celtic fan, you'd admit they don't have much chance.
"I wouldn't say they need a miracle, but it will take a lot of effort, concentration and some good luck.
"They can't afford to concede the first goal. That would finish the game.
"But Celtic must try to attack. They must show the same qualities they did during the first game. They did cause the Juventus defence some problems and to have Georgios Samaras back from injury will be a big boost for the team.
"Georgios has the ability to make a massive difference."