Miguel Delaney: Why the Manchester United job will define Jose Mourinho's career

It was back in December, when it became starkly clear that Manchester City had completed the race for Pep Guardiola’s signature before anyone else had even really started running, that those at Manchester United first realised they were going to need a response. They needed a statement.

The developments across the city did cause some genuine anxiety at the top levels of Old Trafford. From there, the path to Jose Mourinho was set, even if it was further shaped by the fact Louis van Gaal could not keep the team on track for the Champions League places.

United have again failed to qualify for the competition that effectively proclaims elite status, for the second time in three years, so are desperate for the type of appointment that denotes that status; for that assurance that any problems are not deeper than the manager - even if the strong likelihood is they are.

That is why Jose Mourinho is such an obvious fit right now.

The big question is whether that will remain the case, whether the much-discussed differences in the idealised club principles and the traits of the Portuguese’s career will manifest themselves into the eventual problems everyone expects.

So far, the general argument has been that Mourinho’s time at Old Trafford will follow the general trend of his career: immediate positive effect until, by two years in, the very qualities that fired success start to burn things down.

But is that fair? Is it possible the last Chelsea experience - one that amounted to the first undoubted failure of his career, and a spectacular one at that - will cause consideration for change in his management? Will it be a juncture moment, one where he reassesses potential weaknesses in his approach that were not relevant up until 2010?

There is actually one grand difference with this job and every other one he’s had. A key point of negotiation for Mourinho’s representatives was that he will be granted final say on transfers. That is something actually unusual in his career, and empowers him more than any other previous job.

It actually makes this even more of an unknown, beyond the growing argument whether Mourinho is now past his peak. It’s not just that the Portuguese has the kind of managerial circumstances and freedom he’s always wanted, and at a super wealthy club too. It’s that he has the specific job he’s always wanted.

Will all of that, along with the lessons of Chelsea, give him the confidence and capability to move back on to another level as a coach - and recover the winning relentlessness we saw until 2010? Will it free him? Or is he the kind of manager that actually needs these constraints?

There is an argument that the principles of the club - even if they are some way imagined at this point - will provide some constraints. Mourinho is aware of the expectations to play a certain style and to introduce youth, and one of the biggest has been over the future of some of the young players Van Gaal brought through - most obviously Marcus Rashford.

The Portuguese, however, has told people close to him that he thinks the 18-year-old is a quality player and can have a clear role.

But this has always been the thing with Mourinho’s attitude to youth too. He has no problem playing them if they are obviously ready there and then, but just isn’t necessarily willing to give rawer graduates the space to develop in the way Sir Alex Ferguson used to and Mauricio Pochettino does now. That is because his mindset is to do whatever is necessary to win the next game.

This is the fundamental truth, and most relevant point to any discussion of Mourinho. He wants to win now. It is a motivation that dictates any situation with him, and particularly the question of whether he will fit United in the long term. They’ll just have to get used to that too.

Along those lines - but just like Pep Guardiola and Antonio Conte - he wants to overhaul his first XI. Mourinho wants two defenders, a commanding central midfielder, a fast winger to facilitate attacking football and a mobile striker.

United are willing to fund it, and some of those targets - like John Stones, Rafael Varane and, less realistically, Harry Kane - are young players to build a future on.

It’s just such an unknown whether United can properly build a future on Mourinho. In essence, this is going to be the deciding job of his career.

If it follows the trend of all the others, it will be hard to dispute that he is not just a short-term manager only ever capable of firing brilliant but brief success.

If he fails, it will be even harder not to argue he’s finished at this level.

If he succeeds in the long-term, though, he can properly claim much of the criticism was unfair - that he just needed a job like this, the job he wanted for so long.

It is in some ways fitting that it is the United job that has built up to all of this then. This is where he has always wanted to confirm his legacy, the mere appointment almost serving as a seal of approval of his status. It will instead be his true legacy-definer.

It’s possible, though, that he wouldn't want it any other way.