Neil Lennon's side were on the end of a clinical and ruthless display from the Italian champions, who withstood some sustained pressure, especially in the first half, to all but seal their place in the last eight.
But Celtic right-back Mikael Lustig refused to give up all hope of upsetting the odds in Turin on March 6, and told uefa.com: "It's almost mission impossible but miracles have happened in football before. You never know - a penalty, a red card then maybe we're back in the game, but it's really tough now."
Celtic midfielder Kris Commons also held on to some optimism despite his bitter disappointment at the heavy defeat.
Commons said: "We won't be going over there thinking the tie is over. We've got a good set of players and our coach won't let us believe this tie is over.
"If we have a really good night and they play poorly, you get a couple of early goals you just never know, so we'll be going over trying to stamp our authority on the game and get an early goal - that would be ideal for us."
He added: "We had some good build-up play and possession which got us in good areas.
"The keeper made some good saves but you get paid for what happens in both boxes and we couldn't quite get a goal and conceded three sloppy goals which near enough ends our run in the competition.
"It's hard to put into words when those kind of mistakes are happening at this level. It's frustrating but it was one of those games where individual mistakes cost us the game.
"They're a good team but in the first half I think when we put them under pressure they gave the ball away, but in front of goal they were clinical."
- Sports & Recreation
- Mikael Lustig
- Kris Commons
- Neil Lennon