By the end it was a humiliation. Barcelona, the team that have made their reputation on merciless thrashings, know what it feels like to be on the wrong end of a good old-fashioned one themselves. They had been outfought, out-thought and, ultimately, outplayed and, from here, who can possibly see Bayern surrendering this position and not making it to Wembley on 25 May?
A team of Barcelona's refinement are simply not accustomed to being humbled in this manner. They will consider it a deeply chastening experience and perhaps the most astonishing part is that the damage might have been even more grievous. Bayern played with such ambition and superiority it is no exaggeration to say the team 20 points clear at the summit of German football might have added more goals.
Barcelona left with legitimate complaints about the officiating, particularly when Mario Gomez and the outstanding Arjen Robben scored the second and third goals, but they would be kidding themselves if they want to attribute the blame elsewhere.
The manner in which they had crumpled was almost shocking to see. Bayern muzzled Lionel Messi in a way that rarely happens. They were the stronger, fitter unit, the team that played with the greater structure and organisation, and now Barcelona – mighty Barcelona – fully understand why Jupp Heynckes' side have a goal difference of 75 in their favour in the Bundesliga.
It was a rout, the kind of score that is not meant to happen to Messi et al. But they were flat, lacking cohesion, pressed into carelessness, vulnerable in defence and lightweight in attack – everything one would normally consider beneath them. Was it a one-off or something deeper? There were later questions about it being "the end of an era." All that can be said for certain is that they were dishevelled enough to make it a genuine debate.
Bayern, in stark contrast, were tremendous. Robben and Franck Ribéry shimmered with menace on the flanks. Müller, scorer of the first and fourth goals, was a dangerous opponent. Javi Martínez and Bastian Schweinsteiger controlled midfield, ensuring there was never a single part of the match when Messi started to influence the tempo. Barcelona had looked like a flower starved of water when Messi was unable to start the second leg of their quarter-final against Paris Saint-Germain. This time he was there from the beginning, albeit possibly still short of fitness, but was peripheral, looking increasingly forlorn as the game went on, hands on hips and shaking his head. He had a stinker.
Xavi Hernández and Andrés Iniesta could have no meaningful influence. Gerard Piqué, the central figure in defence, affirmed the sense that he is not the most accomplished organiser and Marc Bartra, playing because of injuries to others, barely coped.
The only glimmer of hope for Barcelona is that they have won 15 of their 16 La Liga games at the Camp Nou and put four past Milan a couple of rounds back. These Bayern players, however, are intrepid travellers. Their away record in the Bundesliga stands at 14 wins and one draw from 15 games, 37 goals scored and three conceded. Above all, there is the sense of a Bayern team utterly determined to elevate themselves above the most revered club side of the last decade.
They did so last night in every department, denying Barcelona space, strong in the challenge, quick to the ball but always confident enough in their own ability to play with great ambition rather than the ploys of conservatism the Spanish side's opponents sometimes adopt. What a thought that this side will also have Mario Götze in their ranks next season.
They could have been ahead inside 90 seconds, Robben running though but denied by Víctor Valdés, and Barcelona had still not found their rhythm by the time Müller opened the scoring with a 25th-minute header. Robben clipped in the cross and Dante had the height advantage over Dani Alves for the first chance. His effort was drifting wide but Müller was at the far post and Valdés, not looking wholly convincing, was beaten by a stooping header.
The goal had highlighted Bayern's superiority in the air and it was the same four minutes after the interval. Three players went for the ball when Robben whipped a corner to the far post. Two of them wore Barcelona shirts yet neither with great conviction, certainly not compared with Müller's leap. Gomez was offside when he applied the finishing touch from two yards out but, even then, Barcelona did not appeal with the kind of vigour usually associated with them.
Müller flashed a shot wide, Ribéry had a go from the other side and Robben, hardly known for his aerial prowess, had a free header at goal before the home side went further ahead. Robben worked the ball on to that wonderful left foot, running through the right-hand channel and took full advantage of the referee, Viktor Kassai, not penalising Müller's block on Jordi Alba. Barcelona's players waited for a whistle as Robben expertly slipped his shot past Valdés.
Barcelona, after years of dishing out this kind of trouncing, were now being subjected to Bavarian "olés". Müller slid in to make if four from the substitute Luiz Gustavo's cross and Barcelona's worst defeat in Europe for 16 years was complete.