Celtic boss Neil Lennon hailed his young side as the Bhoys ran out 2-1 winners over Spartak Moscow to secure a spot in the last 16 of the Champions League.
Gary Hooper had put his side ahead after 21 minutes by taking advantage of a defensive error, with Ari equalising with a neat finish before halftime.
But nine minutes from time, after Georgios Samaras was felled by Marek Suchy inside the area, Kris Commons smashed home a winning penalty in off the bar to secure the win – and Lennon gushed about the significance of the progression after the game.
"It means a hell of a lot to the club," Lennon told Sky Sports. "The players first of all, they’ve been magnificent, it’s a monumental achievement on their behalf, for the supporters, the shareholders, the backroom staff and all of the club.
"Just to be at the big table in the New Year is a phenomenal effort, to get the 10 points is a phenomenal effort, so it’s a very good night for us."
The Northern Irishman name-checked two of his former mentors, Gordan Strachan and Martin O'Neill, as inspirations for Celtic’s achievement, before commending the achievements of his inexperienced side.
He continued: "No one gave us a pray going into this group and to qualify, Gordon Strachan did it twice, so to follow in his footsteps and I had great years under Martin O'Neill who taught me more or less everything about the game, if it wasn’t for those two guys I wouldn’t be here, so I’d like to thank them.
"This campaign has been a great learning process for myself, but these young lads have grown and it totally justifies beating Barcelona. Because if we hadn’t have qualified then we would have just been remembered as the team who beat Barcelona, but we’re a lot more than that now, which is fantastic."
Lennon was seen diverting his gaze away from the pitch when Commons was preparing to take the match-winning spot kick, and he admitted after seeing previous unsuccessful attempts he would change tact for Wednesday night’s crucial penalty.
He added: "I watched the last couple of penalties for us and we’ve missed them, so I thought I’d give this one a miss.
"But Kris showed a lot of character and I thought he had a great game tonight for us in all aspects of his game and deserved his goal. He’s taken a real sore one, but we’re hoping he'll be OK for the weekend, but he’s wrote his name down in the club’s folklore."