Twice in four days Barcelona were hauled down from their celestial plane. They were dragged into an unfamiliar place of weariness and frustration.
Have Barcelona been rumbled? To think so would be shallow.
But at home and abroad inside a week they have bounced off walls of defensive rigour while betraying signs of fatigue and a lack of tactical variation.
After their La Liga hopes were effectively ended by Real Madrid's victory on Saturday night, Barca coach Pep Guardiola said: "We've been on this path for a long time. We had a lot of pressure on us starting in August and we haven't stopped. We can't expect to always be up to the standard, but it's a pity we faltered in the decisive moment."
You stride to the Nou Camp in Catalonia's capital expecting another restatement of Barcelona's superiority. Opponents tread there anticipating shades of humiliation.
The passing is ice hockey-quick, the movement incisive, the finishing lethal and the possession stats overwhelming.
At the heart of it all flits the little maestro, Lionel Messi, whose individual brilliance elevates the collective excellence of the men around him.
This is not an elegy for the Barcelona reign, even if Spain's La Liga title has "slipped away", to quote Guardiola, who stepped from the dream team era to improve a kaleidoscopic system of passing by adding ball-retrieving vigour.
The form book still suggests that Chelsea will reap a whirlwind tomorrow from their 1-0 semi-final first-leg lead, which was achieved with tactics broadly similar to those used by Real Madrid in their 2-1 win on the enemy's turf: Jose Mourinho's first victory in a league Clasico.
If Real can overturn Bayern Munich's 2-1 first-leg lead he will also be on track for a third Champions League title, each with different clubs. He would confront either his old London team (Chelsea) or the one he has finally found a way of beating here in Spain. No UEFA coaching badge is needed to see that teams have tried for years to halt Barcelona by packing all 11 players into a defensive block and hoping the ball will circulate harmlessly across the pitch.
This obvious retort to Barca's ball-hogging has resulted in many a slaughter.
But it worked for Chelsea last Wednesday night and it worked again for Mourinho's improved unit, who could draw on the zest of Cristiano Ronaldo to lend force to their counter-attacking zeal.
"We saw that Chelsea beat them. So we know that over the last few years they have been so successful; that they have been playing great, wonderful football. But they are not unbeatable," said Xabi Alonso, the former Liverpool midfielder who patrolled Real's defence, along with Sami Khedira, the first goalscorer.
The difference now is that Barcelona are short of the energy, tempo, conviction and fluidity that made them unplayable for so long.
Now, a 70pc possession rate cannot open the door, even for Messi, who looks a fraction slower and less sure of his angles, his space. His shots cannon into the legs of defenders and often his runs take him across a line of tacklers rather than through the gaps.
Barcelona performed on their own sacred turf like a team who knew the league title had already migrated to Madrid, who are now seven points clear with four games left.
Guardiola's team selection suggested as much. Cesc Fabregas, Pedro, Alexis Sanchez and Gerard Pique all began the night on the bench. The 20-year-old Tello was pinned to the left flank, and exposed as still too nervy in front of goal for games of this intensity.
The odds are still in favour of a Barcelona win in the cauldron here tomorrow, but Chelsea will be computing all the information from Real's victory to help them with their plan.
At Stamford Bridge, Didier Drogba's barnstorming display did the trick in front of banks of wary guardians.
Real were able to call on the even more formidable Ronaldo, whose 42nd league goal of the campaign moved him one ahead of Messi.
Ronaldo was immense in this clash of the empires. He hustled his way down Barcelona's left flank in the space vacated by Dani Alves and seized his chance dazzlingly three minutes after Sanchez's 69th-minute equaliser had cancelled out Khedira's first-half goal.
For once, he was not remotely in Messi's shadow as Barcelona fell to their first home defeat since the 2-0
loss to Hercules in September 2010 -- 55 Nou Camp fixtures ago.
For a team with 169 goals in all competitions to be at risk of ending the season without either of the two biggest prizes is astounding.
Guardiola said: "I'll talk to my players when things have calmed down. We'll focus on next week -- which means we have to focus on Chelsea.
"We hope to recover well and play the game against Chelsea."
Andre Iniesta sounded the most mournful. "It hurts our soul not to be able to prolong the Liga a little more, but we have to accept it," he said. "Our only option was to win and they played with that in mind."
Defensive midfielder Sergio Busquets was the most indignant: "We were faithful to our style of play. But Real Madrid closed themselves off at the back the whole game.
"They didn't play at all, they just looked for the counter, but sometimes football is like that. They did very little to win the game. It's a bit unjust. I hope Tuesday isn't like today."
In their pomp, Barcelona are capable of baffling opponents with their almost striker-less system, but when teams nullify that free-form style there is often no alternative to turn to, and no focus through the centre.
As they chased the game, Guardiola took off Xavi and told Sanchez to play in the centre-forward role. Within seconds he had scored from the position, and Messi was able to switch to a withdrawn ghosting role instead of having to impersonate a No 9.
Guardiola's faith in Tello rebounded as the young winger over-ran the ball and side-footed one of his team's best chances high into the stands.
At the club, there is already a sense that Barca will need more attacking options if the team is to evolve, especially with Xavi's advancing age.
No top European striker would look more at home in this Barcelona squad than Robin van Persie, who has the technique to go with his goal-scoring prowess.
Chelsea's problem is that football's club world champions are accustomed to adversity.
There could be no sharper spur than the threat of elimination from Europe, four days after domestic power shifted to the Bernabeu.
The big guns will doubtless all be back, in a more convincing formation, and lethargy ought to fall away as Chelsea cling to their slender advantage.
But England's last representatives can board the plane encouraged. The glow of Barcelona's football has gone the way of Messi's smile, for now. (© Daily Telegraph, London)