But Efe Ambrose refused to shrink away from the challenge of trying to overturn the 3-0 lead Juventus will carry into tomorrow night's last-16 second leg clash.
The Nigerian defender vowed to fight with "his last breath" to achieve a footballing miracle. He said: "Everything is possible in football. So let's go there and see what happens as I believe there is still a chance. We played well at Celtic Park, but it didn't work in our favour that night. Let´s see what happens in Italy."
Ambrose also told the Celtic View: "We never throw in the towel and keep fighting to our last breath."
Neil Lennon's salvage squad flew out of Glasgow today without three key players. Tony Watt was ruled out after suffering a bruised foot in training yesterday and did not travel. Scott Brown (abductor) and Mikael Lustig (thigh) remain out, but Charlie Mulgrew could return after missing three games with a muscle problem.
Assistant boss Johan Mjallby has warned his players to stay calm if they face the tight marking Juve imposed on the first leg.
Celtic were unable to make the most of 10 corners in their 3-0 first-leg defeat amid a hands-on approach to marking by the Italians.
Gary Hooper and Brown were booked in penalty-box clashes, along with Juventus pair Stephan Lichtsteiner and Simone Padoin.
Mjallby said: "We watched the previous game they played, against Napoli away, and they did the same thing again. They were marking their opponents very, very roughly and hard when it comes to corner-kicks and wide free-kicks against. Hopefully the referee is very strong if it happens again.
"If we give back the same medicine, you never know what is going to happen. We just need to be strong mentally."
Celtic had 10 attempts on target in the first leg and Mjallby wants the players to be positive again.
"Obviously Juventus have a healthy lead and we have a mountain to climb, but we have to believe that we can do it," he said.
"I think we can take a lot of pride if we can win away from home. If this is going to be the last game during this European adventure, we want to finish it on a high.
"We think we have a good enough team to win the game."