IT has been said of Ole Gunnar Solskjaer that he spent so long watching games from the substitutes’ bench that he learned to identify weaknesses in the armoury of opposing defences. Then, when Alex Ferguson would spring him from the bench with Manchester United in need of a goal, he would have a picture in his head of how he was going to inflict maximum damage.

Inevitably, Solskjaer duly obliged. In other words, he knows the value of being able to change a game from the bench. It is where he placed two of his most influential players against West Ham, even if his reasons for doing so were a million miles away from why Ferguson used to do it. The Scot had a wealth of riches all over the pitch, Solskjaer was merely employing some pragmatism at a busy time of the season.

This is an important week for United. The gilded prize of Champions League football in the new year will be decided when they travel to Leipzig on Tuesday evening while a Manchester derby at Old Trafford awaits them next Saturday. Solskjaer hinted before kick-off that he might have one eye on the former when explaining his reason to omit Bruno Fernandes, Marcus Rashford and David de Gea from his starting line-up.

The Norwegian suggested minor injury problems were behind his thinking with Fernandes “kicked from pillar to post” of late, Rashford complaining of a shoulder problem and de Gea struggling with the knee injury that forced him off at half time against Southampton last weekend.

In came Paul Pogba for his first start in a month, Edinson Cavani and Dean Henderson. There was one other change – Donny van de Beek for Fred – and altogether it had a discombobulating effect on United.

Fernandes has now had 15 goal contributions in league and Champions League, good enough for a 47 per cent share of United’s total in both competitions but it was his ability to retain possession and join up the dots that was missing here.

United are something of a curate’s egg at present. One week, they look coherent and the next they look as if the have never seen a ball before. For the first 45 minutes, it was the latter on show. So poor were United that Solskjaer had to abandon all pretence at resting his key players at half time and it was as well that he did with West Ham demonstrating why David Moyes had steered them into fifth, coming into this game.

Jarrod Bowen had the ball in the net after nine minutes but his strike was ruled off-side after the West Ham attacker failed to time his run accurately enough and the cheers of the 2,000 home supporters evaporated as quickly as blown bubbles.

Then Pablo Fornals should have scored for West Ham twice within a couple of minutes just after the half hour. The Spaniard is a frustrating figure, often opting for the wrong decision when well placed. On each occasion here, though, it was simply poor execution that meant he placed his header wide of Henderson’s goal for the first opportunity and toe-poked the ball on to the right-hand post with the second.

It seemed only a matter of time before West Ham scored and so it proved. In the 38th minute, Bowen’s corner was flicked across goal by Declan Rice and Tomas Soucek stabbed it home from a couple of inches.

It should have been 2-0 a minute later when Scott McTominay squandered possession and Fornals released Sebastian Haller. The French striker lumbered forward, rounded Henderson and then slipped just as he was about to pull the trigger with two United defenders on the line. It was the type of chance Michail Antonio – who Haller was replacing due to injury – would have relished.

United were a shambles and found themselves incredibly fortunate to go into the interval only a single goal down.

Against the script, Solskjaer was forced to turn to Fernandes and Rashford for the start of the second half but still United looked flat. West Ham almost doubled their lead when Vladimir Coufal slid the ball to the back post but Bowen could not turn it into the unguarded side of Henderson’s net.

Then, almost imperceptibly, United got a grip on midfield. McTominay struggled to wrap his foot around the ball when he put his shot into the side-netting but Pogba had no such difficulty. Henderson’s punt into the right-hand channel found Fernandes and he purposefully strode across the face of West Ham’s box before slipping the ball to the Frenchman whose first-time shot curled from outside to inside Lukasz Fabianski’s left post.

Controversy ensued with Moyes signalling that Henderson’s pitch-length pass had veered over the touchline. VAR had a look, could not decide and the goal stood, much to Moyes’ visible frustration. Subsequent replays seemed to suggest United were very fortunate.

There were 65 minutes on the clock when the equaliser came, 68 when United took the lead, Mason Greenwood lashing the ball past Fabianski after Alex Telles found him unmarked, loitering on the left edge of the penalty spot.

All the momentum was now with United. Rashford, who hit the post when put through the middle, and Greenwood, who shot wide, should have put the result beyond doubt. The former did just that when striding on to an arcing through ball from another substitute, Juan Mata, and he dinked it over Fabianski to seal the victory.

It was United’s ninth successive away win in the Premier League. Given Solskjaer’s relative struggles it was hard to believe that this victory extended a club record, not least when you consider vintage United teams of the past compared against this current incarnation.

The paucity of United’s play in the first half has become a recurring theme and it could have been messy very quickly had West Ham – who created more chances and had more shots – not been so wasteful.

Question marks over Solskjaer remain even as United moved into the top four, a point ahead of City.