Never mind it is the Europa League and a play-off tie to reach the last 16 at that.
This was an epic duel worthy of the Champions League, between two European heavyweights who will both surely grace that exalted stage again next season. It was a throwback to past classic encounters between these two giants, a thrilling display of attacking football, with both sides intent on winning and no quarter given.
Yet not even the enduring brilliance of Marcus Rashford could earn Manchester United a first victory over Barcelona at the Nou Camp.
The stadium, scene of United's dramatic Treble-clinching Champions League win over Bayern Munich, will always have a special place in their history. But this was the sixth time United have played Barca at the Nou Camp and they have yet to come away with a win, although they came mighty close.
That they failed to do so was down to defensive frailties Barca were able to exploit, Xavi's side going ahead then coming from behind to salvage a draw.
Yet Erik ten Hag deserves huge credit for going to the home of the La Liga leaders and playing with freedom and purpose, rather than for a draw.
Rashford was unplayable, scoring United's first to take his season tally to a career-equalling best of 22, then creating the second to give them the lead.
Defensive naivety allowed Barca a way back into the game, but Xavi and his players know they face a huge task to win at Old Trafford next week and go through, after United went toe-to-toe with the Spanish giants.
United have now lost once in 18 games in all competitions, this fearless performance underling the progress made under Ten Hag in his first season.
Barca dominated the first 20 minutes, with United forced to defend, but they grew into the game and should have taken the lead when Wout Weghorst was put through but sent a tame shot straight at Marc-Andre Ter Stegen.
Ter Stegen made three key saves in the first-half to keep it 0-0 at the break. The second-half began with chances at either end, Raphinha flashing a shot wide and Jadon Sancho snatching at the ball when more composure was needed.
Barca took the lead five minutes after the restart, Marcos Alonso rising above Fred at the far post to head the ball down and beyond De Gea.
United were level three minutes later, Rashford beating Ter Stegen at his near post with a clinical low finish, Fred atoning with the pass to set up the goal.
Ten Hag's side took the lead a minute before the hour, Rashford involved again, skipping past Raphinha before drilling the ball into the six-yard box.
Fernandes flicked the ball on and it came off Barca defender Jules Kounde for an own goal, sending the United fans high up in the stand into delirium.
United appealed for a penalty when Kounde appeared to bring down Rashford as he surged towards the Barca goal in the 64th minute, Ten Hag receiving a yellow card for his angry protests.
“At 2-1, it was a clear foul on Marcus Rashford,” said Ten Hag. “We can discuss if it's inside the box or outside the box, but definitely, it's a red card.
"I asked the referee why. He said it was outside the box and that it was no foul. The linesman and referee were in a very good position to see and I think we had VAR. It's not good, it was a really bad decision. Maybe they were pressed by the pressure Barca made, but they can't be at this high level of European football.
“It's a big influence, not only on this game but in this round, and referees can't make such mistakes."
Barca made it 2-2 in the 76th minute, Raphinha's cross eluding everyone, including team-mate Robert Lewandowski and Raphael Varane, before sailing past De Gea and into the net.
In a frenetic finale, Barca appealed for a penalty for handball against Fred, after which the ball struck De Gea's right-hand post, but United survived.
So it finished honours even ahead of next week's decisive return leg at Old Trafford, which has a lot to live up to after this pulsating encounter.
