In some quarters, Celtic's 93 minutes of defiance against arguably the world's greatest side has been hailed as a tactical masterstroke by Lennon, only undone by Jordi Alba's goal deep in stoppage time. Lennon himself would not regard his own tactics as the defining characteristic of a proud night for him and his club, though. His success in Camp Nou – success which withstood the entirely predictable outcome of an eventual Barcelona win – instead should be measured in other ways. Namely, his growing ability to identify highly promising players and blend them into a highly motivated team.
Celtic didn't do anything innovative in Camp Nou. The attempt to live with Barcelona was helped by the fact umpteen other clubs have previously tried every trick in the book in a usually fruitless attempt to do so, so all the tactical templates are widely known including trying to suffocate their majestic playmakers. Lennon sent out a back four with four midfielders protecting them – entirely routine – although there was the courageous twist of playing with two forwards, Georgios Samaras and Gary Hooper alternating between front man and secondary striker.
There was no "anti-football" strategy from Celtic. They were forced to chase shadows for most of the night, almost constantly on the back foot, because Barcelona's brilliance reduced them to that. Lennon had not sent out his team only to defend, but like the vast majority of visitors in Camp Nou they had no say in the matter.
What was admirable about the display wasn't any tactical sophistication in what Fraser Forster, Kelvin Wilson, Efe Ambrose, Victor Wanyama, Joe Ledley and Charlie Mulgrew did, but in the discipline and enormous commitment they and the other Celtic players showed in working themselves to the point of exhaustion against a team that made almost 1000 passes.
They worked tirelessly and were constantly switched on to react to Barcelona's endless interrogation. Lennon had spent time hammering it home to his players that the Catalan side could inflict damage from the first second to the very last – how right he was – but they followed his orders almost perfectly. Iniesta's goal was too well-executed to be realistically preventable although James Forrest let his concentration slip for a crucial moment and wasn't aggressive enough in tracking Alba's run at the killer goal. That was all it took.
Being able to just about survive the mauling teams get in Barcelona inevitably invites a reassessment of this Celtic side. How far can it go? It is Lennon's team. He signed nine of the 11 players who started and the combined fee spent to assemble the entire side was only £13.3m, plus another £1.5m-worth of used substitutes. Martin O'Neill twice earned draws in Barcelona but his teams were different: they contained seasoned professionals assembled for relatively high fees. Lennon has put together a group on a modest budget, every one of whom is playing at a higher level now than he did at his previous clubs.
Without airbrushing the fact they left the stadium as losers, Camp Nou witnessed further evidence that Celtic have learned how to play away from home in Europe. "We have shown this season that we deserve our place alongside Europe's elite clubs," said chief executive Peter Lawwell.
One of the lessons from folding 3-0 at Braga, 4-0 at Utrecht and 3-1 at Sion in the manager's first two full seasons was that he did not have the defenders he needed. A number have moved on, while Mikael Lustig and Kelvin Wilson are looking like better players than they did at first, Ambrose has been immediately impressive, Emilio Izaguirre is recovering form and Mulgrew and especially Wanyama have been invaluable. All of them will be required again for the ordeal of dealing with Barcelona again at Parkhead on November 7. Samaras and Scott Brown may miss that tie through injury, but Celtic left Spain with no psychological wounds.
Group G could yet slip away from them, perhaps if they lose to Barcelona and Spartak Moscow beat Benfica again, but Tuesday night will surely have lasting relevance for this team. There was a sense from the players after the match that they had pretty much handled the stiffest test they will ever face in football, which will empower them for any subsequent challenge.
"Normally, when a team comes here, Barcelona will beat them easily," said Biram Kayal, the Celtic midfielder. "That hasn't happened to us. There is a big difference in this team from one year ago, the team has gelled now. Most of us have been together for two years now, almost three, and there is a lot of power there now. We have a lot of confidence and we feel anything is possible.
"We always believed we can do something at this level. We had difficulties in the past when we played away from home but that is no longer the case. Before Barcelona, we hadn't lost away in almost a year. And now it's taken a goal right at the end to beat us. We believe it's possible to qualify."