There is an entire strand of this Paul Pogba debate, it strikes me, that seems to have been entirely overlooked. As United’s record signing drifts in and out of the Manchester United first team, his every movement scrutinised for signs of nefarious intent, proxy slight or total warfare, perhaps there is a more prosaic explanation for all this. Perhaps Jose Mourinho just really, really likes Scott McTominay.

That, certainly, was the theory under examination here, as United held Sevilla to a dicey and occasionally tempestuous goalless draw in the Champions League last 16.

As things turned out, Pogba’s exile from the United first-team lasted exactly 16 minutes, as Ander Herrera’s early injury saw him introduced as a substitute. But more on him later. For on a tempestuous Andalucian night, United’s 21-year-old academy graduate stepped into a giant pair of boots and delivered a performance of beguiling anonymity.

Which is, of course, by no means a criticism. Beguiling anonymity is the very quality McTominay was picked to provide. Even the announcer at the Estadio Ramon Sanchez Pizjuan seemed to have trouble identifying him. (“Scott… McTominigh!” was his best effort.)

And for a player deployed in the very centre of the pitch, McTominay paradoxically did not so much run the game as run after it, run towards it, run around it, his every measured stride simply marking time until the next. He left no footprints, exuded no vapour trails. The YouTube highlights reel of McTominay’s performance here would consist solely of him running, set to something like Enya.

From the start his function was clear: to close down Sevilla’s midfield two of Ever Banega and Steven N’Zonzi, not by hacking them down or committing to the challenge, but simply by being there. He wasn’t really pivotal going forward or going back. In short, he simply was, and for a manager whose foremost demand from a midfield in these games is presence - that they be where he wants them to be - McTominay did pretty much everything that was asked of him.

Scott McTominay says he remains 'concentrated and focused' after Manchester United's draw in Sevilla

What he didn’t do, really, was touch the ball. His job was neither to win the ball, nor to use it creatively, but simply to deter it, funnel it, parcel it off somewhere else. Even his sole shot of the game, a left-footed curler from 25 yards, felt measured and respectful: on target, testing goalkeeper Sergio Rico but never seriously challenging him.

The one time he tried a clever reverse ball to Juan Mata, he lost possession. The one time he tried to cross into a packed penalty area, late in the game, he failed to clear the first man.

Jose Mourinho's gamble largely paid off (Getty)

In one sense, it was a left-field choice: throw an untried rookie into your biggest fixture of the season ahead of your garlanded A-list star. On another, though, it was perhaps the ultimate Mourinho selection. The arrival of Alexis Sanchez has hastened the evolution of this United team as one that likes to attack directly, dynamically, rather than building play through midfield. Throw in Mourinho’s natural instinct in these European away games to stifle and thwart, to hang in there rather than try to kill the tie off, and McTominay’s selection makes perfect sense.

“You ask three questions, three about Pogba, don't you have any other questions?” Mourinho snapped angrily at BT Sport’s interviewer ahead of the game. And above all, you suspect that what he likes most about McTominay is that he is everything Pogba is not: unheralded, unstarry, anonymous. There is also, surely, a part of him that relishes upending his popular caricature as a chequebook manager by picking a home-grown rookie over an £89m marquee signing with his own welcome hashtag.

It didn't take long for Paul Pogba to make an appearance (Getty)

Of course, even with the best will in the world, you could never seriously argue that McTominay has half the talent of Pogba. Yet in a United side full of players who like to try things, perhaps there is a certain worth - a certain wisdom, even - in having a player who tries absolutely nothing.