The Amazon Prime access-all-areas documentary of Ralf Rangnick’s 24-match Premier League tenure as Manchester United interim manager might be entitled “Finish Fourth”. Or, alternatively “The Gamble”.

Because, make no mistake: if the German, who watched this harum-scarum United victory over Arsenal on a picnic blanket to keep warm in the posh seats, has not lifted them into a Champions League place when match-day No 38 is over he will have failed. And, despite the billing of Rangnick and his career achievements, being parachuted in for a six-month Red Adair act is the latest dice-throw from United in the eight years and now six managers since Sir Alex Ferguson retired.

Fourth place is the minimum requirement of a season that, though in freefall until Ole Gunnar Solskjær was sacked after the 4-1 capitulation at Watford, can – and should – be turned around. For encouragement Rangnick can look at the XI sent out by Michael Carrick that was led by the stellar talents of Bruno Fernandes, Marcus Rashford, Cristiano Ronaldo and Jadon Sancho, and which missed Raphaël Varane, Paul Pogba (both injured) and Mason Greenwood (a replacement).

Then there is United’s sequence of league fixtures over the next three months. “Kind” is one word for these, a “gift” to the new No 1 another.

Because after this jittery showing come 13 games prior to the derby at Manchester City on 5 March, predominantly against teams at the bottom end of the league table.

Zero forensic analysis is required to comprehend how these matches are a golden chance for Rangnick to gather a 30-plus haul of points from the 39 on offer, and make a real push for the top four. On the glass half-empty side, though, is the inescapable truth of how a group which finished second last season, and which was strengthened by Ronaldo, Sancho and Varane in the summer, failed to win a single league outing in October and were 15 points behind the leaders, Chelsea, at kick-off.

Cristiano Ronaldo celebrates with Jadon Sancho
Cristiano Ronaldo celebrates with Jadon Sancho. Ronaldo’s two goals helped United to a 3-2 victory over Arsenal. Photograph: Shutterstock

The evidence for why was present once more against the Gunners. United’s flaky midfield and defence is antithesis of news, so sorting this has to be the top, middle and bottom of Rangnick’s in-tray. How Mikel Arteta’s free-flowing side scored the opener was akin to a microcosm of United’s ills. Arsenal peppered David de Gea’s goal with a series of corners the Spaniard’s teammates could not clear before, from the next, a hapless Fred stood on the keeper, who hit the turf, and Emile Smith Rowe found the empty net.

If this was farcical there is, too, a legitimate question regarding the calibre of Rangnick himself. The “highlights” of the German’s CV feature a second-place Bundesliga finish with Schalke in 2004-5 (they trailed in 14 points behind Bayern Munich), and a DFB Pokal Cup triumph plus a Champions League semi-final six years later with the same side in a second, truncated six-month tenure before he stepped away citing chronic fatigue.

At 63 years old Rangnick has never managed outside his homeland and it is a decade since he led any side for more than a full season (Hoffenheim, 2006-11). This, then, is hardly a battle-hardened coach who arrives fresh from numerous recent campaigns plotting the downfall of opponents.

And to read the historical quotes currently being pored over from Rangnick is to feel slightly underwhelmed by a man renowned, apparently, as the “godfather of pressing”. The United Review programme for this contest recycled a now familiar Rangnick trope in which he characterises what is common to all elite coaches: “They know what their football looks like.”

The suspicion here is that this is, surely, a prerequisite for any manager at any level. So while United can be applauded for signing up the analytical anti-Solskjær, Rangnick remains a man untested in English football who is about to embark on the severest of challenges.

United’s equaliser arrived via the misfiring Fernandes – his first in 16 United outings – before Ronaldo finished a move initiated by Diogo Dalot, Martin Ødegaard levelled, then Ronaldo again converted – the winning penalty (and career goal No 801).

What remained, though, was the inescapable truth that this is a scattergun side. What they miss is another S-word as synonymous with Rangnick as gegenpressing – structure. How much of this he can apply will determine how successful United will be, and define his time at the club.

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For the shake-up required of the rearguard, Rangnick can note Dalot’s impressive showing at right-back, and pray for Varane to recover quickly so he can bolster central defence. In the spluttering engine room Donny van de Beek surely deserves a chance.

The XI Rangnick sends out against Palace will offer the first clues to all of this.