Neil Lennon believes his side's qualification for the last-16 of the Champions League was the perfect response to those who doubted him, after a dramatic late penalty put his side through.
Kris Commons' spot kick ten minutes from time rattled in off the bar to give the Scottish champions a 2-1 win over Spartak Moscow in Glasgow.
With Benfica drawing against Barcelona, the result was enough to book a place in the knockout stages for Celtic for the first time in five years.
The Parkhead men had to fight their way through two qualifying rounds and were then unfancied when drawn alongside the Russian club, Benfica and Barcelona and the Celtic manager was referring to that scepticism when he said: "It means the world to me as a young manager in my first year in the Champions League to qualify with 10 points, I am very proud of the players, they have performed a miracle.
"People laughed at me when I said at the start that my target was to qualify.
"No one gave us a prayer going into this group but we have qualified and deservedly so. I think you could see the players progressing last year.
"We have some really talented players who I felt could play at European level.
"I didn't want them just to be remembered for beating Barcelona but we have beaten Barcelona and qualified for the last-16 and that is a fantastic feather to have in your cap."
Celtic took the lead on 21 minutes against the run of play after Spartak defender Juan Insaurralde miscued an attempt to cut out a through ball from Giorgious Samaras, allowing Gary Hooper to drill the ball home past goalkeeper Sergei Pesyakov.
As play swept from end to end, Celtic captain Scott Brown had a first-time effort from 16 yards saved by Pesyakov but Spartak's equaliser, when it came, was well deserved.
Emmanuel Emenike's strength allowed him to bounce his way through several attempted tackles before he laid the ball wide to Ari, whose chip beat Fraser Forster.
A nervy second half saw Celtic handed their lifeline when Marek Suchy barged Samaras in the box, with Commons hammered the ball high past Pesyakov and in off the bar.
Their second-place finish in the group means Celtic will face a tough test in the knockout stages, with the prospect of facing Manchester United, Malaga, Juventus, Bayern Munich, Borussia Dortmund, Schalke or PSG .
"It is going to be really tough, against the top teams in the groups," said Lennon.
"You just don't know what shape teams are going to be in two or three months' time. But we are there, we are going to enjoy it and we want to progress as far as we can in the competition.
"Who knows where it can take you?
"The spirit is fantastic, we have some quality players, they have put everything into the group and they have grown as the campaign has gone on and some of them have enhanced their reputations no end.
"The draw is on the 20th and it is something that we look forward to, I just want them to concentrate on domestic duties now."
Spartak caretaker coach Valery Karpin "didn't want to talk about the referee" with regards Celtic's penalty, however, he was mostly magnanimous in defeat.
He said: "I would like to congratulate Celtic, they deserved it because they have had a very good Champions League campaign.
"The referee blew his whistle for a penalty so it was a penalty.
"The first half was the probably the best we have played in a long time, so it is disappointing to lose matches when you play well.
"In the second half the three midfielders who were supporting the striker were not so influential.
"But I cannot blame any of our players, I have to thank them and the fans who came to Glasgow to support us when the game did not mean anything to us."
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