Manchester United‘s fine start to the season, winning six of their seven Premier League fixtures to sit level on points with Manchester City at the top of the table, has come with a caveat: the fixture list, thus far, has been kind to them.
The only points the Red Devils have dropped came via a 2-2 draw way to Stoke City, while Everton, swept aside 4-0 at Old Trafford, represent the most difficult opponent on paper that they have faced to date.
But that all changes when the Premier League action resumes at the weekend, with José Mourinho's men facing the task of a trip to Anfield to take on bitter rivals Liverpool. And they'll do so without Paul Pogba and Marouane Fellaini, both of whom are out injured.
Pogba has been out since mid-September after picking up a hamstring injury against CSKA Moscow in the Champions League, and the £89million Frenchman isn't expected to return until November or later.
Fellaini, a much-maligned figure at Old Trafford since his 2013 move from Everton, has become increasingly key under Mourinho, and his recent form will mean that he'll be missed by United.
Throughout his career, Mourinho has always tended to take a cautious approach in big games, emphasising defensive rigidity and doing all in his power to limit errors, rather than looking to play a more expansive, attacking style.
Indeed, in last season's 0-0 draw away to Liverpool, the Portuguese manager came in for more than his share of criticism due to his choice of tactics. The 20-time champions lined up nominally in a 4-3-3 shape, but with Marcus Rashford and Ashley Young dropping deep from their wing positions to augment the backline, United effectively utilised a six-man defence for much of the game.
With key injuries in central midfield limiting his options, we've suggested three possible line-ups Mourinho could go with for the tricky trip to Merseyside.
Mourinho has favoured a 4-2-3-1 set-up so far this season, with new signing Nemanja Matić a revelation in one of the double-pivot roles, helping free up Pogba initially, and taking a more proactive role since the former Juventus star's injury.
Fellaini's absence doesn't necessarily mean United must move away from 4-2-3-1, as Ander Herrera, last season's Player of the Year, can come straight into the line-up. But Mourinho's natural caution in such fixtures would suggest he would perhaps prefer to add an extra body in midfield, particular up against Liverpool's likely three-man central trio.
The Reds, should they field Emre Can – reportedly a Manchester United transfer target – Jordan Henderson and Philippe Coutinho in the middle of the park, may give Mourinho cause to feel uneasy about playing three attacking midfielders behind Romelu Lukaku, potentially leaving his side exposed and overrun.
Last season, 4-3-3 was Mourinho's go-to formation when faced with a high-ranked opponent. The only time he veered away from this plan was the early-season 4-0 mauling at the hands of Chelsea at Stamford Bridge, with lessons learned about the risk of 4-2-3-1 against a dynamic and clinical side.
As such, the former Porto and Real Madrid coach might see fit to revisit 4-3-3 for the trip to Liverpool, once again opening up the possibility of using defensive wingers to aid the defence and counteract the Reds' threat in wide areas.
For that reason, despite his recent form, it is unlikely that Mourinho would start with Anthony Martial. The French attacker has been sublime this season yet his playing time continues to be limited. If he starts at Anfield, it will be a sign of a more expansive outlook from the United boss.
There is reason to believe that Mourinho may no longer view 4-3-3 as a necessity in the big games; namely that, in Matić, he now has the kind of dedicated midfield destroyer capable of offering sufficient defensive cover, affording him the use of an additional attacking player.
This formation also means that 36-year-old Michael Carrick will be required to start – unless Daley Blind is risked in midfield which seems highly unlikely. The veteran midfielder has more top-level experience than any other member of the United squad, and is the club captain. But at this stage of his career, his mobility and press resistance would be a worry against a side with Liverpool's energy.
Furthermore, Carrick is an injury doubt, too. So if Mourinho is intent on using 4-3-3, and the former England midfielder and Blind are not viable options in central midfield, 20-year-old Scott McTominay may have to be thrust into the fray, which doesn't seem a very Mourinho move.
The option that would give United the most tactical flexibility would be 3-4-3. When out of possession, the wing-backs can tuck in alongside the wide centre-backs to support against the danger posed by Mohamed Salah and Sadio Mané, while the inside-forwards could drop in alongside Matić and Herrera to augment the midfield.
In this system, the option of using Jesse Lingard as part of the front three, with his positional versatility, work rate, and ability to stick to a defensive task, could prove valuable.
This shape also gives United the best counter-attacking options when possession is won, packing the wide areas with pace while offering the inside-forwards the kind of defensive back-up to enable them to transition without fear.