Jim White: 'Gulf in class obvious as limited United fail to ruffle Barca feathers'
There was a hint of what lay ahead even as the teams lined up in the tunnel before kick-off in this Champions League quarter-final.
Leading out the visiting Barcelona side was Lionel Messi. And, alongside him, at the head of the Manchester United team, was Ashley Young.
The player many would suggest is the greatest the world has ever seen up against a bloke some would argue might struggle to be described as the best right-back in his own household: as a visual marker of the scale of the disparity between the two sides, it was telling.
In the press room before the game, the television screens were showing extensive highlights of United's victory over Paris St-Germain in the previous round.
As wishful thinking went it was up there with Theresa May thinking anyone would agree with her Brexit policy.
A win like that against an opponent of this scale would surely require resources beyond United's current possibilities.
Diogo Dalot, Scott McTominay and Fred attempting to better Ivan Rakitic, Sergio Busquets and Philippe Coutinho: this was Championship against Champions League, the result of a perfect storm of five years of poor planning, and inadequate buying.
The prevailing hope among the home fans was that their new manager, Ole Gunnar Solskjaer, had not yet exhausted his astonishing reservoir of escapes in this competition.
Apparently tailored by the gilets jaunes, Barcelona stepped out on to the Old Trafford pitch in a vivid splurge of fluorescence. And it was not just their outfits that stood out.
They were soon passing, passing and passing again, leaving United trailing, befuddled in their wash. In midfield we had Arthur against Fred, its nomenclature suggesting this was a scrap staged in a 1950s working men's club.
The reality was slightly more chastening.
And then there was Messi. Initially the assumption was that Dalot might man-mark him, follow him around the pitch, squeeze down his room for manoeuvre. But as the game began there was no sign of that.
In fact, it appeared as if nobody was picking him up. The policy seemed to be to ignore him and hope he went away. But the thing about Messi is, for all the periods of apparent indolence, one moment is all he ever needs. One moment to accelerate from the traps. One moment to find the perfect ball. One moment to switch from uninterest to unstoppable.
Only a quarter of an hour had gone when he decided to intervene. Taking the ball on the edge of the United penalty area, he suddenly applied the afterburners, sped sideways to the fringes of the box and found himself with the room to caress a delightful disguised chip of a cross to the far post.
Apparently only he had noted that Luis Suarez was completely unattended there. And the Uruguayan, perhaps the most unpopular opponent to play at Old Trafford, duly accepted the unmissable invitation to nod the ball home.
Initially the goal was ruled out. But VAR, United's saviour in Paris, could not help here.
Replays quickly recognised there had been no infringement in the build-up.
As the referee signalled that the goal would stand, Suarez celebrated extravagantly in front of the Stretford End.
And no wonder: Marcus Rashford's entire first-team career at United has unfolded in the time since he last scored an away goal in the Champions League.
Though it turned out he would have to wait a little longer: the ball had, in fact, been diverted in via Luke Shaw's shoulder.
The next time Messi was noticed was when he was smacked across the nose by Chris Smalling in the unequal effort of challenging for a header.
Blood poured freely. As he was attended to by the medics, the crowd sang Viva Ronaldo, a pointed celebration of their old favourite and Messi's perpetual rival.
He didn't look perturbed. He wiped himself down and continued to lurk, forever looking for the ball, forever poised ready to pounce.
And with him there, Barca could relax. In truth, for much of the game they didn't do much more than relax.
Occasionally required to contain United as they huffed and puffed and did their best to challenge assumption, the visitors did what was necessary.
Bring it on, Smalling had challenged Messi before the game.
That he wasn't really required to do anything other than operate in second gear was the most telling indictment he needed to serve up.