It’s been three years since the forward burst into Manchester United’s first team and he looks better than ever now José Mourinho has been sent packing

There is a famous photo of Marcus Rashford lining up with his teammates before an England Under-16s fixture. Glancing down the row of likely lads you notice an adorably baby-faced Joe Gomez, the youthful Dominic Solanke, looking pretty much the same as the adult Dominic Solanke, and towards the far end a gap in the line where a face should be.

Except, look closer and there is someone there, almost blocked from view by the looming outline of the small girl standing in front of him. Yes, it’s Rashford. And yes, he’s tiny, peeping out between the schoolkids with the same sense of quiet poise that has carried him through the past three years, almost to the day, since his debut for Manchester United.

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It is a personal anniversary that will be marked on Sunday by another epic-looking engagement. Rashford is likely to start up front in the early spring blockbuster against Liverpool at Old Trafford. This is the kind of game he likes. There have been some barren scoring spells during those three years but also goals against Liverpool, Chelsea, Arsenal, Manchester City (twice) and Spurs, not to mention Spain home and away last year.

Plus, of course, Rashford is now United’s first-choice No 9, reward for his development under Ole Gunnar Solskjær and another stage ticked off for a player who has always seemed to be growing in one way or another. Both literally – an inch and a half in height since that debut against Midtjylland – and also as an inbetweener at this level, all talent and potential energy, just looking for a space to fit.

Facebook Twitter Pinterest England Under-16s line up against Wales in November 2012 and Marcus Rashford (back row, third left) can barely see over the mascot. Photograph: David Rawcliffe/Propaganda

The influence of Solskjær, his fifth club and country manager, has been profound. As recently as October there was talk of Rashford needing to move away from Old Trafford to progress. Fast forward 10 weeks and such is the rush of post-José goodwill, the sense of a club rediscovering something of its own mythology for attacking play and on-brand homegrown youth, you could make a case that Rashford is now the single most important person at Manchester United.

He has had to cling to the rigging at times. Even that spectacular debut three years ago on Monday had its random elements. Rashford would not have been close to the squad if United had not had 14 players out injured. He would not have been there to take the call had United accepted a loan offer from Crewe shortly before. He would not have started had Anthony Martial not twanged a hamstring in the warm-up (Rashford told his mum not to even bother turning up, he was so unlikely to play). He might not have made any impression at all if Louis van Gaal had not sat him down at half‑time and told him to stop running so much, to linger more in front of goal.

Rashford listened, scored twice in the second half, then got two more against Arsenal three days later on his league debut. Still adjusting to playing centrally, still being urged to acquire “a real goal addiction” by his under-18s coach, Paul McGuinness, Rashford was flushed right out into the light, asked to complete his final growth spurt in public.

Since then it has been, as Louis would say, a process. Albeit one that takes in the false turns as well as the good times. Such is the rush to junk every part of the Mourinho regime it is often assumed he did nothing but obstruct Rashford’s progress. Take away the José years and Rashford has 12 goals in 31 games for United under his first and last managers.

Facebook Twitter Pinterest Marcus Rashford delights the Old Trafford crowd for the first time after scoring against Midtjylland on his Manchester United debut on 25 February 2016. Photograph: Oli Scarff/AFP/Getty Images

But Mourinho is a big part of this story, if only as confirmation of Rashford’s ability to adapt and survive. He has never seemed disheartened at United, even when others have suggested he was being misused, even as Mourinho capered on to the touchline in cinematic rage at a missed chance, then spoke darkly afterwards about the poverty of his attack. Character is destiny in football. Sometimes simply refusing to go away is the greatest gift of all.

As ever the question is just how good he can become. A couple of weeks ago there was a timely reality check in the direct comparison at Old Trafford with Kylian Mbappé, another prodigious 20-year-old and the gold standard when it comes to universe-boss attacking potential.

It is not a fair match-up for anyone. Mbappé is ready-made, already out there streaking away from the pack. Rashford is just one of those chasing, helped now by the perfect fit between his own best qualities and Solskjær’s tactical blueprint, which alternates between an energetic high press and full‑throttle counterattack.

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Rashford makes so many fine runs his presence has also been a natural catalyst in the blooming of Paul Pogba’s full range of passing. Encouraged to use the ball as a weapon rather than simply keep it or chase it, Rashford has begun to show off his own tricksiness and quick feet. For a while he would say he wanted to play like Neymar, to rove across the front line, to create as well as score. It seemed fanciful at times. But check his stats for the second half of the season and he is up there in all the metrics, offering goals, assists, passes, tackles, dribbles (everything except headers won: a man still growing into his own height).

The feeling with Rashford is always that there is more to give, more space to grow into. He has a Ronaldo-level dedication to training and breathtaking speed over longer distances. It was this ability to wait on the left wing and then make perfectly timed runs behind Trent Alexander‑Arnold that marked his best display under Mourinho, the 2-1 defeat of Liverpool almost a year ago.

Rashford will play more centrally on Sunday but Solskjær is too cute in his tailored attacking patterns not to have explored the idea of straying into that same area, seeking the same match-up.

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Either way, Rashford has a clear run to the end of a season that has seen him linked (spuriously perhaps) with moves to Real Madrid and Barcelona but has provided above all confirmation of his importance to United.

There is an element of the golden child about this. Rashford has something redemptive about him, a quality that goes against the chaos and dissolution of the post-Fergie years. He rebuts, to a degree, the narrative of doom and decay, of a club being stripped away of all that is good; proof instead that good people are still present, and that a youth system so often compared unfavourably with Manchester City’s is still operational.

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Despite the mongering of doom, the sense of drift and flux, Rashford remains the only academy product of genuine A-list quality to emerge since the class of 1992, and the first homegrown central striker of real quality since Mark Hughes. His presence provides a link to United’s best traditions, a focus in the short term of all that renewed goodwill; and, in the long term, perhaps something more, an attacking talent with no obvious ceiling, still looking to grow, to find its own peak.