IT was a matter of belief.
It took a great strike by Gary Hooper and a late, contentious penalty from Kris Commons but Celtic's progress to the knockout stages of the Champions League was underpinned by a communal faith that sustained the team through a dramatic group campaign.
Fraser Forster, the goalkeeper who did so much to defy Barcelona in the critical matches of the group, reflected on a superb night for the club by stating: "When the draw was made for the group stages, a lot of people wrote us off. A lot of people have things to say and their opinions and that is up to them. But there is not just great skill, but great character among the squad and we have shown everybody what we can do. We are delighted to be in the hat for the knockout phase and now we have to wait and see who we get. We'll be delighted whatever happens."
The goalkeeper, who has been called up to the England squad this season, praised the winner from Commons as a "great strike", adding: "He decided to go straight down the middle and it was a little bit heart in mouth at one stage, but it went into the the net and that is all that matters."
Celtic's progress was helped by Barcelona drawing against Benfica but the goalkeeper said: "We had to focus on our own job during the game and not worry about what they were doing, but luckily, Barca did enough for us.
"It was just a case of us grinding through the game. I don't think that is the best we have played in the competition this season, but there were some great performances. [Georgios] Samaras, for example, was different class. He really put himself around and could not have done much more for the team."
But how did the team attain such levels for a challenging campaign? "Well the crowd speaks for itself in the home games and the belief we have as a team gives us great confidence within the dressing room," said Forster.
Biram Kayal, the Israeli midfielder, also invoked the importance of self-belief and a faith in the team. "We believed we could make the last 16 and we did our job in every game we played in the Champions League," he said. "We believe in ourselves, especially at Celtic Park and to get seven points from our games here is unbelievable. There should be huge respect for the manager and the players for achieving this."
He insisted, too, that the team could go further in the competition. "We always believe we can do it here. We have beaten the best teams in Europe here and played good football," he said. "I am really happy for the fans but especially for the players. I think this is the best moment for everyone here. "
He said he always suspected Celtic would play above their seeding. "Before we got into the Champions League, people asked me if it was possible for Celtic to get there after a break from it for four years. But we also believed and we have gained a lot of experience. Now we seeing a lot of our players taking themselves to the next level.
"We are mentally stronger now and we have a lot more experience. When I came here I was just a 20-year-old boy and a lot of the players were about the same age. Now we have experience of playing in the Europa League last season and winning the championship and that has helped us."