Barcelona had to wait until the last minute of time added on for the winning goal and, although the persistence was a result of their domination of possession, Celtic's defending was rugged. Forster made some impressive saves, and the overall sense was of a team unwilling to be overawed by the occasion.
There are times when opponents must accept that Barcelona are capable of playing an attacking game that is impossible to stem. The home side's equaliser in Camp Nou involved a series of sharp angled passes that outmanoeuvred the Celtic defence. The winning goal was hardly conventional, either, since the right-back, Dani Alves, crossed for the left-back, Jordi Alba, to score. Forster might have felt the most aggrieved, since he pulled off a number of remarkable saves, but the frustrations were shared.
"I was fairly happy with the game, but I was disappointed with the result," Forster said. "When you lose, it doesn't matter if you play well, it's meaningless. Their first goal was a typical Barcelona goal. I don't think there is anything that could have been done differently. It was just an unbelievable bit of skill."
Forster does not anticipate another siege of the Celtic goal tonight, though. Barcelona will not be affected by the atmosphere, but the demand will be for the home side to be more dynamic. Celtic believe the Spanish side are vulnerable at set pieces, but they don't intend to let them settle into the kind of rhythm will allow them to hoard possession.
"It will be different, we are playing at home," Forster added. "It will obviously be a tough game but we will have home advantage and we will have the crowd on our side. It has the potential to be slightly different. It's going to be a highly emotional night for 60,000 people inside the stadium but it's us who will need to be ice cold."