It was tight. They needed a very dubious penalty. But Celtic are through.
Few gave them any chance to progress once the draw for the group stage was made, with the general consensus being that even a Europa League place might prove unrealistic.
In a group in which Barcelona were expected to run away with the top spot, Spartak Moscow and Benfica would be left to fight over the remaining place in the last sixteen.
ITV Football's reaction on Twitter (which is now removed, via Goal.com) was memorable: “Bye bye Celtic. They've drawn Barcelona, Benfica and Spartak Moscow.”
Neil Lennon and Celtic happened to see things differently.
An opening day draw with Benfica left many supporters worrying that they'd missed their chance. Traditionally, Celtic's success in Europe has been down to their impressive home record, with few points picked up on the road.
Yet although they'd faced relatively weak opposition in the qualifying rounds in Helsingborgs and HJK, there had been signs of improvement in performances away from home (even going as far back as last season's trip to Udinese), and Celtic pulled off an impressive 3-2 win away to Moscow with a late Georgios Samaras goal securing the three points.
Heartbreak was to follow at the Nou Camp, where after taking the lead Celtic were pegged back and eventually succumbed to what felt like an inevitable Jordi Alba winner late in stoppage time, but the real turning point came in the return game, where goals from Victor Wanyama and teenager Tony Watt saw Celtic claim an incredible win against perhaps the most celebrated side in the history of the game.
A point would have been enough in Lisbon against Benfica to guarantee qualification, but a nervy performance yielded an all-too-familiar away defeat, and Celtic headed into their final game at home to Spartak Moscow knowing that a win or a draw would be enough, provided it was better than what Benfica managed to get in Barcelona.
On a night fraught with tension which saw agonising misses, contentious refereeing decisions and a manager unable to watch as his team scored the winning goal from the penalty spot, only one thing really mattered.
Once again, Celtic defied the odds and qualified for the last sixteen.
As it stands, few would fancy them to advance any further, but these are probably the same people who doubted they were capable of making it past the group stage.
Celtic will find it tough regardless of which team they draw, but with the pressure entirely on the opposition, who knows?
They've shocked Europe more than once this season. There's every chance they can do it again.
Why? Let's take a look