It was the morning after the night before and a lad sporting a yellow bobble hat was reaching through railings to grasp at pens and smartphones.

Jadon Sancho — just 18 — had become the second youngest Englishman to score a Champions League goal 14 hours earlier and was the last Borussia Dortmund star off the training pitch, signing autographs for a large number of the 1,200 fans watching a weekly session open to the public.

The mood in Brackel, a small district of Dortmund, was understandably buzzing. Atletico Madrid had been beaten 4-0, their worst European defeat for nine years. Sancho had scored four minutes after coming on and was the man of the moment, but the win had deeper meaning for a club who are top of the Bundesliga.

After making the move from Manchester City, Jadon Sancho has become a star in Germany

Sancho dazzled for Borussia Dortmund in their recent European victory over Atletico Madrid

'You saw the starting line-up,' said Lars Ricken, a one-club man and now academy director. 'Reus, Gotze, Pulisic and Bruun Larsen: four players who were educated in our youth department. It's one reason why the atmosphere in the stadium is so great. There is that identity with the fans.'

Ricken could broaden his point by mentioning 20-year-old defenders Achraf Hakimi (on loan from Real Madrid) and Dan-Axel Zagadou, 19, who signed from Paris Saint-Germain just before Sancho last year. Dortmund pride themselves on the development of young footballers and half the regular first team are 22 or under.

Fifteen months have passed since Sancho left Manchester City for £8million. He has forced his way into Lucien Favre's starting XI and his tally of six assists this term is the most in the division.

The youngster is now forming the core of the squad alongside the likes of Marco Reus

In fact, his assist-per-minute ratio cannot be matched across Europe's top five leagues. A new contract has been signed until 2022 for someone now valued at around £100m. There are calls for Gareth Southgate to hand out a full England debut in Thursday's friendly against the USA.

Sebastian Kehl, another club legend who is a key cog in the management machine, explains they are now targeting these shores with purpose.

'The focus is on the English market,' he said. 'Jadon is a good example. We take a lot of care over our scouting. In England, the young players haven't been getting the chance to play because the structure of the clubs and squads is totally different. It could be a good thing for us. But we have to be fast. If we're not fast, then...'

Then others will steal a march. Yet it is Dortmund, four points clear of Borussia Monchengladbach in the Bundesliga after beating fifth-placed Bayern Munich 3-2 on Saturday, who have been doing that for some time.

Two matches during a tournament in Turkey were enough to persuade them to sign the now well-established Christian Pulisic, who will line up for the USA against England.

The finest bit of business was Ousmane Dembele, signed from Rennes, whose six league goals and run in the team led to Barcelona paying around £93m for him after just a year.

'The offer was so big,' said Kehl. 'Then the decision is, "OK, we have to sell to get new players and create some more". It's like a circle.'

There are plenty more, Sancho not even being the latest. 'Sergio Gomez, who's 18, left Barcelona's La Masia to come here. That's a sign,' Kehl said. 'We've tried to make him stronger and he should be the next guy.' Sancho, already a senior England international, is being watched by half of Europe.

Sebastian Kehl - a key cog in recruitment - says Dortmund will target more English youngsters

Dortmund strenuously deny they are a selling club and it is intriguing to hear the reasons behind his sudden elevation. Chiefly, not playing much during his debut season and learning to fend for himself.

'It takes a while,' Kehl said. 'Everything was new for him last year. His family travel over sometimes but normally he is on his own. It's not as if someone is close to him every moment. They don't go to the supermarket with him.

'He has to stand on his own feet, cross the street alone. We are available. You are taken care of but we're not doing everything. There has to be a point where a player has to do it on his own. It's personality development.'

Sancho has been shown huge photos of club icons on the walls at the Westfalenstadion and challenged to get himself up there. He is made to study German twice a week, the importance of which was drummed into him on his arrival. The winger admits it is a struggle but he is persisting.

'There are enough examples of talented kids who thought they were better than they were,' Sancho said. 'I'm a normal kid.'

Language is viewed as the crucial tool to integration. 'It's not easy for him but he's doing a really good job,' said Kehl. 'He's getting more educated and more convinced. You can see he's a game-changer. He makes a difference. He has the mental quality now. He's more involved and getting better and better.'

Regular meetings with manager Favre and the first-team analysts are where Sancho is being developed in a technical sense.

They took Sancho on a tour of the city before he chose to leave England, a move motivated by the prospect of opportunity. Locals say football is the only uniting factor in an area which has lost most of its industry, hence ticket prices remaining low.

Young talent believe in the vision, as shown when Sergio Gomez (R) left Barca for Dortmund

The idea of buying youngsters came as Dortmund were staring at financial meltdown in 2005. Ricken, a Champions League winner in 1997, cites sales of former Germany striker David Odonkor to Real Betis in 2006 and Mario Gotze to Bayern in 2013 as examples of selling to reinvest.

'It's not to buy stars, but create them,' Ricken added. 'We've had a rebuilding phase because one year (2016) we lost Hummels, Gundogan and Mkhitaryan and the next we lost Aubameyang and Dembele. The solution was not to buy older players, with a couple of exceptions.'

One of those exceptions, Axel Witsel, was plastered across the front of newspaper Bild after scoring against Atletico. He trains yards away from the youth teams. As Kehl bowls around in a golf buggy from one meeting to the next, young kids are encouraged to introduce themselves. In fact, everyone introduces themselves.

Then there is the Under 13 session conducted solely in English by Tim Kirk, a coach from Bath. His arrival in 2016, after giving up his day job as an English and PE teacher, reveals an awful lot about Dortmund's attitude towards their academy.

'I got to know (Under 19 coach) Benny Hoffmann when he was running the Under 13s,' Kirk explained. 'I'd helped start a district schools organisation in Bath and Wiltshire, where we focused on values and the social side. We've had 76 from that programme turn professional.

'I was invited here for a week. Lars asked me to see what I thought. From that report a job offer arrived. We were in Lithuania recently and took them to the KGB museum. That throws up all sorts of questions about communism and capitalism. They have to tidy their own rooms, do bed linen and they have to buy and cook the food themselves.'

The majority of academy prospects are from the region. Seventeen are staying in the Dortmund house at their training complex under the watchful eye of a family, and Ricken claims they have very few scouts scouring Europe, instead relying on contacts. 'We don't collect players. Only the very best,' he said.

Dortmund recogised the potential in Sancho and worked hard to bring him to Germany

It feels relevant that his office is next door to that of sporting director Michael Zorc, who has been known to promote teenagers to the first-team environment himself, most notably under Jurgen Klopp. 'We have made a name for ourselves for not only signing talent but trusting them and giving them time,' Zorc said.

Promotion is no issue, age no number, as shown by 13-year-old Youssoufa Moukoko scoring 40 goals in 28 games for the Under 17s as they won the title last season.

So, back to that 4-0 win over Atletico. One potential academy signing, who had been on a tour of the city earlier in the day, was planted on the gargantuan Yellow Wall for a taste of things to come.

'Wow,' was his first word on hearing the deafening noise inside one of Europe's true coliseums. Dortmund have some product to sell.