In the second leg of the Copa el Rey, Real Madrid essentially replicated AC Milan's disciplined job on Barcelona, except they did it classier and they did it at the Camp Nou. Against Milan, Barcelona struggled with the likes of Stephan El-Shaarawy and Giampaolo Pazzini running at them on the break. Against Real Madrid, it was Angel Di Maria and Cristiano Ronaldo. The result was a devastating victory, and while Barcelona may, with some justification, point out that it was the least important of the three trophies they will contest, it has the potential to be a highly traumatic defeat for the club.
At the root of all this is something that their exceptional performances have obscured. Barcelona have, essentially, not progressed in five years. Their transfer activity over the whole period has been nothing less than a disaster - only the fact they were starting from such a ludicrously high standard has kept them from wasting their prime years.
In that period, their only objectively good signing has been Jordi Alba, and that was a total no-brainer - a Spanish left-back, who had progressed hugely, cemented his place in the national team, and was available on the cheap due to an expiring contract. Other than that, it's been a story of oversights, wasted money, and unfulfilled potential.
Their frontline in 2008 consisted of Thierry Henry, Samuel Eto'o and Lionel Messi. They have undoubtedly improved in that respect, but most of that has been replacing the ageing Henry on the left flank, the emergence of Pedro, and the astonishing progression of Messi. David Villa has been an incredible disappointment - perhaps the finest goalscorer in the world when he was signed from Valencia, he was immediately marginalised on the left wing and has struggled for fitness and form as a result.
Then there was the deal for Zlatan Ibrahimovic. There was an arrogance in discarding him so recklessly, and we cannot be certain where it came from, but it must undoubtedly go down as one of the worst pieces of transfer business of all time. Having jettisoned Samuel Eto'o, an astonishing player with a rare combination of discipline, selflessness, and ruthless goalscoring ability, Zlatan Ibrahimovic replaced him at ludicrous expense. The experiment was abandoned after a year, at the cost of around 60 million Euros, as Barcelona refused to play to the strengths of their new signing and saw themselves stifled in Europe by a team that, gloriously, contained Eto'o and was led by their future nemesis in Mourinho.
The signing of Alexis Sanchez was one of several Barcelona could have made, and he has been peripheral in the side's achievements since he was signed and not really developed into the level that was hoped.
In midfield, the same problems have been magnified. Yaya Toure was shipped off to Manchester City and replaced with the more cerebral Sergio Busquets. It was a move that was widely praised for it's genius and progression in the ethos of ball retention and homegrown players, but it has ultimately left Barcelona with one less option and style of playing as Toure has gone on to show his exceptional talent in the Premier League.
Cesc Fabregas was also added to the mix, and yet he has had his potential and talent utterly wasted - instead of introducing him as one of the few players who could play alongside Xavi or Iniesta and not look out of his depth, as part of a rotation policy that would break their over-reliance on the strength of their first eleven, either he or Iniesta have been shunted out to the wing to accommodate him.
It is open to question where the blame for this lies. Ultimately, it must be shared between managerial and boardroom level. Zlatan Ibrahimovic was a deal that made sense - a superior ball-player than Eto'o, and a powerful option in the air. The foolish decision to ditch him after one season belongs to the higher-ups, but it was the two legs against Inter Milan in the Champions League that did for him, where Pep Guardiola bafflingly deployed him as a battering ram against a team that were defending deep and denying him space. A combination of misuse and impatience resulted in a huge financial loss.
Ultimately though, the ethos that has guided Barcelona in the past five years has been found wanting. On the pitch, teamwork, pressing and possession football have been devastating. But when taken to an ideological extreme, and used as the basis of a transfer policy, it has been a total disaster. The desire to purify that brand of football was responsible for the thinking that produced all of these disasters in the transfer market.
Let's look at the justification for them. Replacing one of the finest goalscorers in recent times in Samuel Eto'o with an inferior player in Ibrahimovic was a decision made because the latter was supposedly better on the ball (whilst ignoring Eto'o's pace, discipline, and team play.)
Crucially against Madrid and Milan, Barcelona's susceptibility to the counter-attack has been due to a lack of a true athletic presence in midfield and the weakness of their centre-backs. Gerard Pique may be a fine ball-player, but he is not in the top tier of defenders in the world at the moment. Busquets may be an astute reader of the game and a fine passer of the ball, but he does not have the athleticism required to deal with a rapid counter-attack. In overlooking these areas, Barcelona paid the price. It's not just the players they've let go from their own team, either - the likes of Nemanja Vidic and Thiago Silva have been available for transfer during the period and ignored.
Whether in the decision to buy, get rid of, or use players, Barcelona's strict adherence to their philosophy has held them back. They had such a good team to begin with that they have been able to accumulate trophies at a phenomenal rate despite the stagnation, but they have been reliant on a first eleven and unable to switch to a squad-based system that has left them both jaded and struggling for alternative plans when faced with resolute opposition. It is a miracle their team has not burned out already, but in future, they may do well to stray somewhat from their policy. Tiki-taka may have been a remarkable success on the pitch, but it's also been responsible for almost every bad decision the club has made in recent years. As a tactic, it works better than any other. As an all-pervasive, dogmatic ideology, it's prevented a great side from being the greatest.