1. Who partners Eric Bailly in the centre of defence?
It's easy to forget Bailly's only 22, has less than 70 first team appearances and is adapting to a new club and country
Manchester United conceded just one goal in the opening three matches, but have since shipped six in their last three games in all competitions. It's arguable that they have come up against a better quality of striker recently, although four of those goals have come from midfielders and Troy Deeney's late strike for Watford was from the penalty spot.
Eric Bailly has featured in every game so far and the former Espanyol centre-back started life at Old Trafford comfortably, as he demonstrated his on-the-ball finesse and positional sense. However, he did struggle against the pace and power of Deeney and Odion Ighalo. It's easy to forget he's only 22, has fewer than 70 first team appearances and is adapting to a new club and country.
Blind or Smalling?
Jose Mourinho likes to build his teams around a solid base, but Daley Blind's performance in the derby has seen him removed from the starting XI. He failed to anticipate Kevin De Bruyne's touch and could only watch as the Belgian raced through to open the scoring for Manchester City, whilst he played Kelechi Iheanacho onside as the away team doubled their advantage.
Chris Smalling has featured in the previous two encounters and is certainly a better defender than the Dutchman. Blind is more vocal when it comes to organising the back four than Smalling, though, which has led to the conundrum that Mourinho has to deal with until at least January.
2. Does Pogba need a two-man or three-man midfield?
Paul Pogba's best displays for Juventus came in a three-man midfield, which would either require United to lose the No.10 role or use a diamond and dispense of the wingers. The squad has an abundance of options for the playmaker role behind the striker, although so far none have proven to be indispensable.
The Frenchman showed flashes of brilliance on his debut against Southampton, but if Mourinho wants him to play with that freedom in every game he will likely need more protection. "I don't know in which position he played," joked the coach after the Friday night game with the Saints.
Pogba's midfield prompting
Having paid a world record fee for his talent, it's natural to build a team around him and want to give him the best environment to succeed. United did line-up in a 4-3-3 versus Watford, but the manager changed back to his usual formation at half-time with both Pogba and Wayne Rooney ineffective.
Mourinho has predominantly used a 4-2-3-1 system since his Internazionale team won the treble in 2009-10, but prior to this he built his success at Porto and Chelsea with three central midfielders. Pogba appears to need some tactically astute teammates alongside him, with neither Rooney or Maroune Fellaini particularly ticking that box.
3. Who anchors the midfield?
Since he arrived in Manchester, Fellaini has played in all three central midfield positions. Under David Moyes it was more box-to-box alongside Michael Carrick, although the Belgian only started 15 league matches.
In fairness to Fellaini he has done fairly well in the holding role, with a high frequency of ball recoveries and a decent array of passing
Louis van Gaal felt that his physical presence would be best served behind the striker, in order to provide flick-ons and win second balls. However, Mourinho has decided that his brute strength is ideal for breaking up possession in front of the back four.
In fairness to Fellaini he has done fairly well in the holding role, with a high frequency of ball recoveries and a decent array of passing. He did struggle with the mobility of City's dynamic midfielders, whilst Carrick could offer a similar skill-set only with greater tactical discipline and stronger distribution.
Fellaini and Herrera under the microscope
Mourinho did use Ander Herrera as a deep-lying playmaker in the second 45 minutes against City. The Basque's lack of physicality would be less of an issue with Pogba and Morgan Schneiderlin further in-front. Blind is another option should he not be required in defence, although Phil Jones is injured once again.
4. What do you do with Wayne Rooney?
United fans have been unhappy with Rooney's displays for some time, with many perplexed as to how he still starts for the club. Both Mourinho and England boss Sam Allardyce have kept the attacker as captain, which surely makes it even harder to remove him from their sides.
"You can tell me his pass is amazing but my pass is amazing too without pressure," Mourinho seemingly belittled Rooney's desire to play in midfield during the manager's presentation. "For me he will be a No.9 or a No.10 or even a nine-and-a-half, but with me he will never be a No.6 or even a No.8."
Rooney's influence against Watford
The Special One backtracked on the statement by deploying Rooney alongside Pogba against Watford, although the subsequent display will only have reaffirmed his initial thoughts. Rooney's only goal of the campaign came against Bournemouth, a header redirecting a mishit shot from Anthony Martial.
The Red Devils and Rooney might profit from taking him out of the limelight for at least a couple of matches (and that may now happen after the forward played for 90 minutes in midweek), whilst Mourinho has to give the player an ultimatum regarding his positioning or risk everyone ignoring his instructions.
5. Has he got the patience to deal with Henrikh Mkhitaryan and Memphis Depay?
Mourinho's treatment of De Bruyne when at Chelsea is just one example of the coach not thinking of the long-term future. The Portuguese boss didn't waste any time on the City star, even though he had undoubted ability.
"If you have a player knocking on your door and crying every day he wants to leave, you have to make a decision," admitted Mourinho last summer. He probably could have persuaded him not to go to Germany, but he got £18 million for the winger and won the Premier League 18 months later.
So far so little…
Henrikh Mkhitaryan has started only one match for United and that ended badly as he was removed at half-time. The attacking midfielder took a season to adapt at Borussia Dortmund, but proved to be one of their best players in the next two seasons.
Memphis Depay had a disappointing first campaign at Carrington and may have benefitted from a loan move this summer. Mourinho is unlikely to wait too long for either player to improve.
