There will be some who will wish the union was more long lasting and United were not trying to secure the services of Sporting coach Ruben Amorim to replace Erik ten Hag, who was sacked on Monday.

Roshelle from nearby Wythenshawe certainly fell into that category.

"He [Ten Hag] should have gone in the summer,” she told me before the game. "It happening wasn’t a shock but maybe the timing was.

"I would have preferred it if Ruud had got the job. He has all the history with the club.

"I didn’t actually know who he [Amorim] was. He is unbeaten in his own country and that is good. But that is not here. Ruud played here. He knows what the game is like here.

"But if that is the way it is going, I obviously hope it works out because it has not been good enough for too long."

Van Nistelrooy said after the game he would be willing to help the club "in any capacity".

On Thursday, that will be to sit in front of the media and conduct a news conference to talk about Sunday’s game against Chelsea at Old Trafford.

It is likely, but not certain, Van Nistelrooy will still be in charge for that game. Indeed, there is a growing feeling it may be the international break in late November when Amorim finally severs ties with Sporting.

United have been here before, drinking in the euphoria of a famous ex-player succeeding as interim boss.

Ryan Giggs beat Norwich 4-0 in April 2014 when he stepped in for four games following David Moyes’ dismissal. Michael Carrick won 2-0 in Villarreal when he took over for three games after Ole Gunnar Solskjaer’s exit in 2021.

Solskjaer, of course, got the job full-time after initially taking over from Jose Mourinho as an interim in 2018. United also scored five, at Cardiff, in Solskjaer’s first match in charge.

“I will text Ole about this,” smiled Van Nistelrooy when he spoke to MUTV at the end of the game.

United failed to score four goals in a first half under Ten Hag, as they did against Leicester.

Yet Van Nistelrooy was honest enough to admit they had created more and better chances at Crystal Palace, Fenerbahce and West Ham this season and won none of those games. Sometimes, he admitted, you need "a little bit of luck".

Leicester boss Steve Cooper remarked that he was surprised at the atmosphere inside Old Trafford: "It wasn’t what we were expecting. It wasn’t intimidating at all. It was good to play in."

That is a bit harsh. United’s fans got behind their team and they provided a performance.

Van Nistelrooy was clearly focused.

In the first few minutes he was so embroiled in the game he was halfway across Cooper’s technical area before he was guided back to his own by fourth official Michael Salisbury.

His celebration of Casemiro’s opener was that of a man who was living a new reality having enjoyed so many memorable Old Trafford days 20 years earlier.

He made a point of having a word with both Marcus Rashford and Alejandro Garnacho when he replaced them during the second half. He will know more than most how valuable confidence is for an attacking player.

His demeanour was one of professional pride and a determination to do his job properly and to the best of his ability.

We do not know what Ten Hag thought, or what Amorim made of the victory, or a quarter-final trip to Tottenham, which will almost certainly be his to fulfil in the middle of next month.

Van Nistelrooy cannot know how many more days there will be. But he does know, on this one, he did well – and he enjoyed it.