Of all the great clubs who have fallen at Parkhead - Juventus , AC Milan and Manchester United - are among those vanquished at Celtic's riotous theatre over the past decade. None is bigger than Barcelona though. And, no matter how long the stadium stands, it is unlikely that any occasion will better Wednesday's terrifying yet successful tangle with Lionel Messi.

How long did the game last? To most of the 55,000 fans present, it seemed like at least nine hours. And yet Barcelona, holding the ball for a full three-quarters of the game, could not score until stoppage time. There, Messi finally beat Celtic's heroic goalkeeper Fraser Forster. By then Celtic were two up. It was too little, too late for the consummate technicians from Catalonia.

The first goal had come midway through the first half from Victor Wanyama, the muscular young Kenyan who has made such an impact this season. Celtic's second goal, six minutes from the end of normal time, gave way to a new bright star.

Tony Watt is the name. The 18-year-old played soccer just for fun until four years ago, when he responded to a newspaper article in which Airdrie United asked local kids to turn up for trials. Watt passed his and, after making the first team, attracted bigger clubs including Liverpool and Celtic's bitter rivals Rangers.

Celtic were determined and got him for a basic transfer fee of $120,000, which has never seemed more ludicrously low than when Watt chased a long clearance from Forster, surged through as the great Xavi missed it and beat Victor Valdes with precocious majesty. His pace took him nearly to the whites of the goalkeeper's eyes minutes later - only for Javier Mascherano to deny him with a desperate and, according to Dutch referee Bjorn Kuipers, legal challenge.

Then came Messi's close-range finish and, finally, the whistle confirming that Celtic had three points. With the one obtained from Benfica at Parkhead and three from Spartak Moscow in Russia, the total puts Neil Lennon's team in with an excellent chance of qualifying for the knockout stages. This would be a much-needed boost for Scottish soccer in the wake of Rangers' financial meltdown and the sacking of national coach Craig Levein after it became apparent that there would be neither kilts nor tartan caps at the World Cup in Brazil.

The night was about drama as much as points; about players who were sustained by the fuel of crowd fervor as they strained to the limits. It was the day after the 125th anniversary of Celtic's formation in club football. Lennon said of the precise timing, ''I just wanted them to make sure they did themselves justice on this night - and they've exceeded that. They've beaten the best team in the world.''

And the qualities that enabled them to do it? "Teamwork" was the first word Lennon used. "Discipline" was the second. Not for the first time on this Champions League journey, he had come up with the right answer. Meanwhile the celebrations began while fans deserved their pat on the back too. They had never flagged.

When the music stopped, they got started. Amplified music, often the enemy of atmosphere in world soccer, did not deter the Celtic faithful who duly waited for it to stop before beginning the incessant barrage of ear-numbing chants that makes European nights at Parkhead a special experience.

This is a truly great stadium, as redolent of history as Fenway Park but on a scale closer to the Meadowlands. Celtic's birthday only heightened the passion of a crowd daring to hope for a miracle - Lennon's men had, after all, come within seconds of forcing a tie in Spain two week earlier - but ready for a taste of the reality that Barcelona right now are back on their pedestal as the world's best.

Lennon was under no illusions. The Celtic coach, whose judicious planning has been a feature of the campaign, followed the approach of Jose Mourinho and Roberto Di Matteo, whose Inter and Chelsea defended even at home in knockout contests against Barcelona in 2010 and 2012 respectively.

No one would suggest that Celtic's players are on the same technical level as either of those sides, each of whom went on the win the Champions League. But the tactics worked and, when Celtic split the dark, drizzly skies above Glasgow's East End by taking the lead after 21 minutes, no neutral would have grudged it.

Wanyama's fearsome challenge left Jordi Albi vainly whimpering and led to the forcing of a corner that Charlie Mulgrew flighted beyond the far post, finding Wanyama, whose header rocketed beyond Valdes amid an explosion on the green-and-white slopes.

Messi hit the crossbar, Alexis Sanchez nodded against a post, but Celtic survived. The Hoops' goalkeeper made a sensational double save from Sanchez and a flying one-hander from Mess. And finally, among other impressive stops before Watt's heroics, on for Mikael Lustig, scored Celtic's second. What a riposte to the daunting arrivals of Barcelona substitutes David Villa, Cesc Fabregas and Gerard Pique.

What a night. Happy birthday, dear Celtic.