In the week that the Scottish champions marked their 125th birthday, goals from Victor Wanyama and teenager Tony Watt gave Celtic their greatest international success since they beat Inter Milan to lift the European Cup in Lisbon in 1967.
"This is mind-blowing, this is Celtic 2, Barcelona 0," a match commentator exclaimed when Watt scored Celtic's second with seven minutes to play before adding at the final whistle: "Wow, wow wow! A phenomenal result for [manager] Neil Lennon and his legends in hoops."
NEWSCeltic record historic win over Barcelona
Among the passionate Celtic fans, rock star Rod Stewart was seen with tears in his eyes as Celtic gave him and the 55,000 ecstatic fans in the stadium reasons to believe they had just seen something very special.
Celtic were only narrowly beaten by Barca at the Camp Nou two weeks ago, and while they were praised for their resilience in that 2-1 defeat, this 2-1 success - despite Barca having 84 per cent possession of the ball - represents one of the biggest upsets in the Champions League for years.
Even the English editions of Britain's papers hailed their victory in banner headlines on Thursday with the Daily Mirror and Daily Mail giving them precedence over Chelsea and Manchester United's victories against Shakhtar Donetsk and Braga respectively.
The result left Celtic with a strong chance of making it into the last 16.
Barcelona lead Group G with nine points, followed by Celtic on seven, Benfica on four and Spartak Moscow bottom with three.
Celtic's remaining games are at Benfica on Nov. 20 and at home to Spartak on December 5 but if Barca beat Spartak in their next match as seems likely, Celtic will only need a draw in Lisbon to qualify.
Lennon, who could hardly contain his joy at the end, said afterwards it was one of the greatest nights of his career and he hoped it would help restore pride in Scottish football.
Celtic's Old Firm rivals Rangers, the country's other traditional powerhouses, have been demoted to the fourth tier after going into administration and Craig Levein was sacked from his role as national team manager after Scotland's miserable start to their World Cup qualifying campaign.
Heart of Midlothian are now in a severe financial crisis which could end with them being wound-up, so Wednesday's victory was a welcome relief - at least for Scottish neutrals.
"This is a great footballing country with great history whether it be club wise or nationally and it has produced some of the greatest players to play the game," Lennon said.
"It's had a lull but when we came into this competition we wanted to gain respect for the players, for the club, because it has a great reputation, and for the game here and I hope that it's given the game a huge boost.
"We've just beaten the best team in the world," Lennon said afterwards.
"The players have just had two of the severest examinations they will ever get in their career and come through it with flying colours."
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