Gary Neville had a point: there was more than a suggestion of Dog and Duck about this game, and not just because of all the misplaced passes in the first half and Marouane Fellaini flinging himself around as if trying to give pub defenders a bad name. Yet you do not see too many park teams playing with three at the back. Much was made of Louis van Gaal’s preference for such a system when the Dutch coach first arrived and here he returned to it in adversity to great effect, with Antonio Valencia and Ashley Young excelling as attacking wing-backs.

Injuries forced Manchester United to name a side with only two recognised defenders, Jonny Evans and Phil Jones, and both were starting their first games in more than a month. While Brendan Rodgers eschewed his regular strikers in favour of promoting Raheem Sterling to free-range front-runner, Van Gaal went with a front five no less, with Fellaini pushing on from the rear and the two converted wingers completing what must have been one of the most adventurous and attacking lineups ever to feature in a north-west derby.

When the game started it was a mild surprise the home side did not form a moving knot of players around the ball school-playground style. Instead they made the most of Michael Carrick’s composure and distribution in the centre of the back three and though it took United a while to find space against Liverpool’s effective early pressing, well before half-time they had made their attacking superiority count.

Despite Van Gaal’s praise for Robin van Persie in midweek and his preference for James Wilson over Radamel Falcao on account of his pace, it was actually Wayne Rooney and the near-forgotten Juan Mata, shoehorned into the same midfield, who proved the most effective attacking players. The wing-backs laid on the opening goals but Rooney and Mata, allowed a surprising amount of time and space by Liverpool, ran the game from the middle of the pitch.

Ironically, given United’s commitment to getting forward, they were being jeered by their own supporters for going backwards in the buildup to the first goal. The Old Trafford crowd could not contain its disappointment when a free-kick in an attacking position was played back across the halfway line and ended up with United losing possession in their own half. David de Gea had to come to the rescue after Adam Lallana cleverly presented Sterling with the game’s first clear shooting opportunity.

Facebook Twitter Pinterest Louis van Gaal explains his decision to play Wayne Rooney in midfield against Liverpool

Had Sterling taken that chance Liverpool might have had a more rewarding time; as it was United cleared the ball upfield and took the lead themselves. Rooney had been helping out in defence and began the run upfield that would bring him a goal from close to his own goalkeeper. Philippe Coutinho tracked him most of the way but crucially lost him just as Valencia was accelerating past Alberto Moreno and gloriously nutmegging Joe Allen. When a perfect low cross arrived from the right the finish from the United captain was just as impeccable.

Mata’s goal was more controversial. If Van Persie touched on Ashley Young’s cross, as he appeared to do, then Mata was a good couple of yards offside at the far post. Yet even though the goal should not have stood he deserved his reward for starting the move, for it was he who pushed the ball out to Young on the left before trotting into the area to see what would develop. Young had been enjoying himself, beating Glen Johnson then his replacement Kolo Touré down the left, but too often took too long to deliver the cross. This time he whipped the ball in early and it did the trick.

When the third goal arrived it was a creation of the United midfield, with Liverpool leaving a huge hole in the centre of the pitch for Mata to run into. His measured pass found Rooney and had his pass succeeded in finding Van Persie the coup de grace might have been delivered by the goal of the season. Instead Dejan Lovren intervened, breaking up the move but only returning the ball to Mata who found Van Persie by himself. That is the kind of luck Liverpool have been having and it did not get any better when De Gea denied Sterling, then kept out a succession of decent Mario Balotelli attempts with a string of remarkable saves.

Perhaps that was not just luck. Whereas Liverpool dropped their goalkeeper for this game, De Gea picked up his second player-of-the-month award in a row. When a goalkeeper is recognised as the most valuable player it tells you something about the way a team have been playing, and with only two defenders on the pitch it was not surprising to see the goalkeeper kept busy, but this was an assured all-round performance from United and there are players to return to reinforce the back line. If Rodgers is still struggling to match a system to his squad, Van Gaal appears to have found one that works.