Something strange happened in the dying moments of the semi-final. Fernando Torres had just scored the goal that ended Barcelona's hopes of reaching the European Cup final, his eighth in 11 matches against the Catalans. Defeated by Real Madrid in the league, relinquishing the title, Chelsea had now knocked them out of the Champions League. In four days, Barça had lost virtually everything. But no one left and no one whistled; no one stayed silent. Instead, the chant went up. Soon it was going round right the stadium: Ser del Barça és el millor que hi ha! Being Barça fans is the best thing there is!

Not so very long ago, that would have been unthinkable. There was sadness here, but no depression: the pessimism and self-destructive streak that has damaged Barcelona over their history was absent. There was little anger from supporters; instead, gratitude for what this team has achieved and what it might still achieve. What it represents. The league has gone, the European Cup too, but they resisted the conclusion that an era had come to an end.

There was something about this occasion that drew parallels with the Wankdorf Stadium, Berne, in May 1961. That was Barcelona's first European Cup final and came to be known as the final of the square posts; posts that Barcelona hit again and again. Barcelona were defeated by Benfica and they still don't know how. Luis Suárez, at the time the reigning European Footballer of the Year and playing that day, puts it simply: "Madre mía," he says, "it's impossible for something like that ever to happen again."

Some think it did happen again on Tuesday night but the reaction is different. Some believe Berne was the start of a historic fatalism at the club. Barcelona waited 25 years to return to the final – and lost to Steaua Bucharest on penalties after a 0-0 draw, having missed all four spot kicks. It would be 31 years before their first ever European Cup, won under Johan Cruyff against Sampdoria at Wembley in 1992. During that period, whatever could go wrong did go wrong, they said. Pessimism took hold. No one expects it to take 25 years this time.

Cruyff changed Barcelona's mentality first, but optimism and assuredness remained precarious. It is only a few years since Joan Laporta, the most successful president Barcelona have had, faced what was effectively a vote of no confidence. Extracurricular problems contributed but on-field failure was the detonator. Now, Guardiola has completed the job: there is a stability that was absent before. Knives are still taken out but not with quite the speed they once were. The coach has evaded questions about his future, which cannot have helped. He says it is time to discuss the issue. Everyone wants him to stay: no one, looking at the past four days, is calling for a change.

Defeat and the manner of it have led to few suggesting that Barcelona must start over again. Instead, there is a belief that Barcelona have broadly got things right even when things go wrong. Xavi has described results as "an impostor"; the play matters even when results do not follow. No team win every single game. Asked what he would say to the young Barcelona fan crying for the first time last night, Guardiola replied: "Welcome to the club – there will be many more times, too."

The identity and approach remain the same. Commitment to them remain steadfast – publicly at least. The Catalan and Spanish media coincided in calling it cruel. Sport called it a Greek tragedy, its editor insisting that this was not a drama and not the end of an era, even though the league changing hands does indeed represent a shift four years later. On the back, its cartoon gave the score as: those who play with the ball 2, those who "play" with a bus 2.

Luck is never a satisfactory explanation but it does help explain things. Barcelona had more than 40 shots across the two legs; they hit the bar twice and the post twice, they missed a penalty and had a goal correctly ruled out for offside. Petr Cech made saves that Víctor Valdés could not. Chelsea scored three times, all of them in added time at the end of halves. On Tuesday night, Barcelona completed 806 passes to Chelsea's 122; Xavi alone completed more than the entire Chelsea side. In terms of time in possession, Chelsea's had less than 20%. When the ball was launched to Torres, Barcelona had 10 players within 10 yards of the Chelsea area. "We had a bit of luck," Roberto Di Matteo conceded.

Which is not to say luck alone explains Barcelona's exit. The possession statistics raise questions about their use of the ball and there were warnings coming into this game, hints at the problems that lay ahead. In a sense, they are also victims of their own success: it is never easy to unpick an ultra-defensive side yet Barcelona almost oblige opponents to park the bus. It is not that you choose to defend against them, Di Matteo noted, it is that you have to. You have to seek survival. Guardiola's side must find a way of drawing teams out to them.

"I look at the team and I try to think of what we have done wrong to explain why we are not in the final and I can't find anything," Guardiola said. "From the very first day I have said that we have to attack, attack, attack. There are times when we don't find the necessary pausa. Maybe we have to learn that lesson in the future. We have to find the way of attacking better."

That may mean eschewing some of the control, some of the play, for greater efficiency. Guardiola's mantra was recently expressed in English: "I get the ball, I pass the ball; I get the ball, I pass the ball." It is the foundation stone of an approach but "What are you passing the ball for?" is a legitimate question. There are certainly other lessons to be learned, too, and dismissing defeat as nothing more than a freak occurrence would be naive. Barcelona were complicit in their demise on this occasion.

One of those lessons may not be the lesson so often advanced in England: Barcelona need a Plan B, it is said. But do they? And if they do, is it really the obvious opposite that most mean by "Plan B"? It is striking that while some demand urgency – the ball into the area, a target man to hit – Guardiola's analysis was to suggest his side required greater pausa. Is a direct approach any guarantee? After all, Barcelona did briefly try that with Seydou Keita, as they have before with Gerard Piqué, and it failed. Not least because this is not a side built to deliver crosses. Precision may have been more pertinent than another plan.

A Plan B in the traditional sense was also partly behind the thinking in signing Zlatan Ibrahimovic. It did not entirely work (although for six months he was largely successful), and it debilitated the Plan A, which worked so well. By the following season, Guardiola had decided he no longer wanted a Plan B, even though it may have been the player, not the plan, that was at fault. Certainly, the turnover of strikers alongside Lionel Messi suggest a failed search for the right associate.

The notion that Barcelona always play exactly the same way is flawed; Guardiola has sought to change his approach and seek new solutions. But he has also built the team round Messi. More often than not, that works. "If we are here at all it is thanks to Messi," the coach insisted in the aftermath of defeat and no one is going to attack the Argentinian, who has been implausibly brilliant for so long. But Messi and his team-mates reached this semi-final tired, lacking inspiration and freshness.

Guardiola believes that a big squad brings risks but a short squad does too. Barcelona have also lacked variety at vital points: against Chelsea, they seemed to be waiting for Messi; the Argentinian seemed shattered, and sunk by that penalty miss. David Villa's absence through injury, almost ignored at the time, takes on renewed importance now.

Barcelona attacked and attacked; Chelsea defended. They knew what was coming and they dug in, resisting. Only Javier Mascherano shot from distance. Chelsea had no reason to come out to Barcelona. They had no reason to go across to Barcelona either. The idea of opening up the pitch on the outside to create passageways inside works until the opposition know that that is what you seek; then they wait inside until the diversionary tactic gives way to the real attack.

And with more and more men thrown forward, with a lack of physical presence and height, it takes remarkably little to catch them and score. Barcelona defend themselves with control but there will always be a moment when that control slips. Chelsea caught them. Not once, not twice, but three times. Fortune may not have favoured the brave but nor was it entirely capricious in its choice.

Any philosophy contains its risks; recent years have shown that Barcelona's can work. Brilliantly, too. Being a Barcelona fan was the best thing there is. They are not going to turn their backs on it now.