Regular followers of Manchester United cannot recall when, if ever, Louis van Gaal has trusted Juan Mata to start in his best position just off the front man. However, on the night when the manager’s future was on the line, the diminutive Spaniard responded to being offered centre stage by eventually providing the missing magic to save the club from lurching deeper towards crisis, scoring the final goal from his favoured position seven minutes from time.

Only Chris Smalling and Daley Blind have started more Premier League games than Mata this season but invariably the Spanish playmaker, two years after arriving in a helicopter to sign from Chelsea for £37m, has been stationed out wide, not trusted with the responsibility of playing as the creative fulcrum. So it was as much of a surprise as a gamble that Mata was invited back into the side to play behind Wayne Rooney. Also involved in Blind’s goal 25 minutes from time, the 27-year-old slowly but surely rewarded his manager’s faith by prompting the penetration that made the difference.

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Mata said afterwards that United had played with more speed in their approach and there did appear a greater freedom to their play, even if Van Gaal denied he ever restricts them.

The Derby fans were quite kind to Van Gaal initially. They waited until the third minute before suggesting the United manager would be “sacked in the morning”. The pace of Anthony Martial and Jesse Lingard suggested that United should be able to stretch opponents from a lower division both laterally and vertically, manna from heaven for a talented No10 granted the freedom to roam. Still, Mata’s selection in that position was a risk, considering how little Van Gaal has hitherto trusted the former Valencia stylist. His goal at Southampton after a 45-pass move seems more like distant history than four months ago.

United, like Derby, fluctuated between 4-2-3-1 and 4-3-3 but either way Mata had licence to flit about, a privilege that has tended to bring out his intermittent best over the years. With the security of Morgan Schneiderlin and Marouane Fellaini offering defensive and physical ballast behind, and Rooney in fine fettle ahead of him, the stage was set for the diminutive talent to flourish. Notwithstanding United’s territorial dominance after Rooney’s superb opening goal, however, Mata was too peripheral to the early action, despite the centrality of his starting position. For a playmaker with little to contribute defensively, chances need to be created, even if his movement off the ball was always imaginative and fluid. Yet United took their time to add penetration to a first-half masterclass in possession.

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There were deft touches from Mata, exchanging positions with Rooney when the United captain dropped off and then laying the ball back, and the Spaniard always made himself available for a pass. But he was seldom found in dangerous enough positions to make a difference in the first half as Derby were allowed back into the game.

At the other end, two minutes before half-time, after Thorne had equalised when penetrating with a run in behind United’s central midfield wall, Mata produced the kind of drag-back that delights fans when it comes off and infuriates managers when it does not.

It is often argued that United have been playing with too much regimentation this season. Mata might contend he has to get a run in his best position to make his mistakes, to try things that more functional players cannot conceive, that only by daring can United throw off the shackles that have been throttling their traditional sense of adventure. But when Thorne and Bradley Johnson pressed in tandem as Mata pulled the ball back with the sole of his foot, only 10 yards outside his own penalty area, United were suddenly exposed. Only Smalling’s last-gasp tackle prevented Chris Martin from giving Derby the lead.

Skilful, slighter players often produce their best as games become more stretched, when legs tire and spaces appear. Mata, playing higher up the field in the second half, headed just wide from Jesse Lingard’s cross and then invited the winger to cross for Blind to score before applying the finishing touch himself when arriving late to convert Martial’s pull-back late in the game.

Van Gaal’s future should not be decided on such a delicacy as Mata, of course. There should be a wider perspective and three wins from their previous 13 games is obviously not good enough.

But it is the freedom of expression, the kind of style that Mata can offer, that Van Gaal needs to make more integral to his game ethos if he is to survive into a third season.