The goals could dry up, he might fall out with someone, or he will be unable to help Ole Gunnar Solskjaer’s side break new ground.
But just for the moment that still seems some way off and last night he helped prove Spanish opposition no longer hold fears for United in Europe with yet another masterful display.
Two goals from the Portuguese helped to carve open a strangely naive Real Sociedad, the first La Liga side United have beaten in 10 attempts in European competition.
They were his 20th and 21st of a campaign in all competitions.
Marcus Rashford, with a third and Daniel James a fourth completed a rout in a victory that effectively put United in the last 16 with a home tie to come.
United’s last trophy came in this competition in 2017 and this performance served a warning that they could repeat the deal this time round.
Certainly with Fernandes in full flow they should at least repeat their run to at least the semi-finals last season.
The Portuguese magician may be abrasive and sometimes impatient at the failings of others but he makes this side tick. And with him pulling strings who knows how far they can go.
For all that Fernandes was good, Solskjaer deserves credit for getting his tactics spot on as well, for all that he could scarcely have believed they would work out so accurately and well.
It was clear from Solskjaer’s selection – picking James and Mason Greenwood among five changes from the side that drew with West Brom – that he felt pace up front could be the key.
Loading his front line with fliers worked a treat particularly when you had players of the calibre of Fernandes, Alex Telles and Fred capable of finding them.
Given the chances created against the Spaniard’s at times suicidally high line, United could and should have been out of sight by half time.
Rashford made amends for earlier misses latching on to the end of a lovely pass in the left channel by Fred and finishing with aplomb inside Remiro’s far post.
And James, who had one ruled out offside, completed an excellent night with a driving run and finish against tiring legs on the stroke of full time.
A night in Turin counted as an away fixture for United owing to Spanish coronavirus restrictions meaning Sociedad need to keep a clean sheet at at Old Trafford next week.
That’s unlikely, bordering on impossible, based on this showing.
Real Sociedad: Remiro 7; Zaldua 6 (Gorosabel 74), Zubeldia 5, Le Normand 6, Monreal 5; Silva 6, Illarramendi 5 (Guevara 74), Merino 6; Januzaj 5 (Portu 80), Isak 6 (Barrenetxea 80), Oyarzabal 5 (Bautista 86)
Manchester United: Henderson 6; Wan-Bissaka 6, Bailly 5, Maguire 7, Telles 7; McTominay 6 (Matic 60), Fred 7; James 6, FERNANDES 8 (Mata 83), Rashford 7 (Martial 68 6); Greenwood 7 (Amad 83)