By Simon Evans
MANCHESTER, England (Reuters) - The 175th Manchester derby pits a United side unbeaten in 40 home games in all competitions against a City side who have not lost this season in the Premier League.
Pep Guardiola's City currently lead by eight points from United in the standings, giving the game much more significance than just local pride.
Here are five big issues that will go a long way to determining the outcome of Sunday's clash at Old Trafford:
WILL MOURINHO 'PARK THE BUS' AT HOME?
United manager Jose Mourinho received plenty of criticism for the negative way his team approached rivals Liverpool at Anfield in October's goalless draw.
But defending in numbers and attacking on the break is also an approach that can work well for United. Relying on the counter-attack certainly paid off handsomely in the 3-1 win at Arsenal last Saturday, even if United keeper David de Gea had to make a string of saves to keep his side in front.
United are at home, but given City's ability to dominate possession, the game may, tactically at least, be more like an away match for Mourinho's team.
City have produced more passes than any other team in the league this season while United are ranked seventh in that area and it would be no surprise if Guardiola's side enjoy most of the ball.
In recent weeks, United have switched to playing with a three-man defence which allows Antonio Valencia and Ashley Young to attack down the flanks - an attacking formation which matches that of City.
But the loss to suspension of central midfielder Paul Pogba may tempt Mourinho into a more defensive line-up in the centre of the field as he looks to counter the influence of City's key creative midfielder Kevin De Bruyne.
WHO WILL DOMINATE THE FLANKS?
City are great at keeping the ball in the tight spaces in midfield and United, with Serbian enforcer Nemanja Matic expected to be fit, will look to crowd the centre of the park and give De Bruyne and David Silva little room to exploit.
But the key areas are likely to be out wide where City have the speed and skill of Leroy Sane and Raheem Sterling allied with the threat from their wing-backs - Kyle Walker on the right and Fabian Delph on the left.
United match-up well in that area - Valencia was brilliant going forward against Arsenal and can work up and down the right tirelessly, while Young on the left has been one of the biggest positive surprises of the campaign so far for Mourinho.
Anthony Martial, or if preferred Marcus Rashford, have a tendency to play much wider than the typical support striker and that might limit Walker's desire to push forward, lest he leave space behind for United to exploit. If Juan Mata is chosen to replace Pogba, he could offer another wide threat on the right.
Whichever wingers and wing-backs come out on top is going to have a huge impact on the outcome.
CAN UNITED STOP DE BRUYNE?
The stats tell the story. No-one has had more touches of the ball this season in the Premier League than the Belgian. De Bruyne also shares, with team mate David Silva, the most assists with eight so far.
Brilliant with both feet and capable of running at a defence from deep and also delivering the killer pass to City's deadly strike force, De Bruyne has been fundamental to the success of Guardiola's team.
United have in Matic, however, a player who could certainly do a close-marking job but that would rob Mourinho of the Serb's overall role of marshalling the midfield and protecting the defence. It could be a job for Ander Herrera or Marouane Fellaini.
WILL LUKAKU DELIVER WHEN IT MATTERS MOST?
The former Everton forward scored 11 goals in his first 10 appearances for United but has managed just two in his last 12 and while Zlatan Ibrahimovic is fit, Mourinho is unlikely to drop his main striker for the derby.
The big trouble with Romelu Lukaku is that he has struggled throughout his career when facing the top teams. He failed to score against Arsenal, Chelsea, Tottenham and Liverpool this year and since 2014/15 he has only scored five goals in 39 games against the 'big six'.
The Belgian could put all those doubts to bed with a winner against City. But if he misses chances, Mourinho may well turn to the fit-again Swedish great on his bench.
(Reporting by Simon Evans; Editing by Christian Radnedge)