But a run of just two wins in eight league games has left the Reds languishing in sixth place and some critics are already calling for his head.
The preseason hype that surrounded the club following the major signings of Paul Pogba and Zlatan Ibrahimovic has been largely extinguished as the holes in the squad have been exposed in recent weeks.
Two areas in particular have been a long-term weakness for United and are still yet to be fully addressed – centre half and centre midfield.
Both very key parts to the spine of any side, so it is really no wonder #Mourinho is struggling to find consistency.
While Eric Bailly has been a positive addition to the team, questions remain over the backup options – it’s hard to imagine any club winning anything by relying on Phil Jones to stay fit to prevent a partnership of Daley Blind and Marcos Rojo at the back.
And there is clearly a central midfield spot for the taking when Marouane Fellaini is gaining a regular slot alongside Pogba and Ander Herrera or Michael Carrick.
Aside from the big money purchases, United have been renowned for producing a long list of stars from their youth system, and Jesse Lingard, Marcus Rashford, as well as the returning Pogba are leading the latest crop of youngsters to impact the first-team.
So could the Old Trafford club turn to another pair of old academy products to join Pogba in turning their fortunes around?
Step forward Michael Keane and Danny Drinkwater.
Keane, 23, has made great strides since joining Burnley in September 2014, and showed the Reds what they were missing with a standout display during the Clarets’ rearguard effort in the 0-0 stalemate at Old Trafford last week.
The 2012 Reserve Player of the Year is now an experienced performer in the top flight with 33 Premier League appearances to his name, as well as playing a key role in Burnley’s Championship title last term.
After champions Leicester failed with multiple bids to gain his signature this summer, Keane has received back-to-back call-ups for the senior national team and his stock continues to rise with a series of impressive performances.
And with less than two years left on his current deal at Turf Moor, the time is now for United to secure their man to solidify their defensive options.
Elsewhere, Drinkwater is another player on the rise having starred in Leicester’s stunning Premier League winning campaign.
The 26-year-old was harshly left out of England’s Euro 2016 squad, but he is benefiting from experiencing Champions League #Football this season, and would add a winning know-how to the squad that has been missing since the string of departures of the 2012/13 league winning team.
Drinkwater has proven his ability and energy to play in a midfield two, which would allow Pogba more attacking freedom, while his direct forward passing could reignite Rashford’s threat by making the most of his pace in behind defences, similar to Drinkwater’s relationship with current teammate Jamie Vardy.
Re-signing the pair would add to the embarrassment of spending big money on previously dispensable academy products, but United have already shown with the capture of Pogba that they are willing to swallow their pride in order to build a winning squad.