But that avalanche never came and instead this was a night that ended with Erik Ten Hag’s team buried under the debris of their own carelessness. The ramifications of the final ten minutes of this strange game could be felt all the way to Seville next Thursday and to Wembley and beyond.
The bare facts are simple. United did add two goals to the ones scored in the first half by their Austrian midfielder Marcel Sabitzer but they were both in the wrong net.
Defenders Tyrell Malacia and Harry Maguire were the unfortunate men and United will now face next week’s return leg as second favourites in a tie that they had threatened to close out in the first half an hour at Old Trafford.
It is, though, more complicated than that. United have an FA Cup semi-final against Brighton at Wembley three days after their game in Spain and the opportunity to rest players has now gone. More painfully, this was a night that also saw United lose their two first choice central defenders to injury.
Rafael Varane did not come back out after half-time while Lisandro Martinez fell under absolutely no pressure moments after Malacia’s own goal had invited Seville back in to the game in the 83rd minute.
Martinez, so important to United, appeared to clutch the back of his foot before being carried off and if he has indeed suffered an Achilles or calf injury than that could be the end of his season.
So suddenly the matter of failing to win this game feels slightly less important. For Ten Hag and his players, ensuring a top four Premier League finish sits higher on the priority list than winning either the Europa League or the FA Cup.
United are in a good position to that end but there are still nine league games left and they are already without their most important attacking player Marcus Rashford, who watched this game from the stands as he recovers from a groin problem.
For the opening 45 minutes of the game, United did not miss their top scorer at all. Seville looked just as desperately average as their La Liga results suggest them to be this season and United – full of enthusiasm and positive intent – just ran all over them.
By the time we had played thirty minutes, United could have scored three or four goals and had managed two. Anthony Martial played in the absence of Rashford and was impressive in terms of movement and passing while the wide player Antony, so often criticised, was also a danger.
United actually had the ball in the net within 28 seconds as Jadon Sancho ran through and though he was offside it was a sign of things to come. Seville’s back four seemed incapable of keeping a straight defensive line all night and when Sabitzer scored in the 15th and 21st minutes both goals were similar.
The first pass through the heart of the Seville defence was by Bruno Fernandes while the second was from Martial. Sabitzer moved on to both easily and finished well both times, once high and once low.
As United looked to put Seville away early, there were other chances. Antony worked Morocco’s World Cup goalkeeper Yassine Bounou at his near post while another Brazilian, Casemiro, had a shot deflected wide and then planted a header in to Bounou’s midriff from a corner.
United had no reason to fear a turnaround in the game at half-time. De Gea had saved well from a Tanguy Nianzou header just before the break but that been Seville’s only opportunity of the first period. Indeed when Antony broke to curl a strong shot against the bar around the hour mark it seemed United remained as likely to score another goal as concede one.
Ten Hag’s team did fall away, for sure. The certainty and quickness of their first half football became a memory. Still, though, there was little warning of what was to come. Seville were better and braver and more progressive but still rarely looked like scoring.
Ultimately, it all changed after one more missed United opportunity. Substitute Wout Weghorst could have turned on a chance and shot in the 82nd minute but instead laid the ball off to Malacia 15 yards out.
The defender should have scored his first United goal but didn’t, pulling his shot badly. Then, a minute later, Malacia misjudged a cross to his own far post at the other end the whole night began to fall apart.
The pull-back from Seville substitute Jesus Navas – once of Manchester City – would in all likelihood have been cleared had it not struck Malacia, ricocheted on to De Gea and flown in to the goal.
Equally a header from another substitute, Yousef En-Nesyri would not have gone anywhere near goal in the second minute of added time had it not struck Maguire and bounced to De Gea’s right and in for another quite peculiar goal.
So from being almost out of sight, United face a real challenge in southern Spain next week. As for the bigger picture, it is suddenly rather less bright than it was.