For a man whose footballing epiphany came almost 40 years ago and continues to underpin his style of play, Ralf Rangnick maintains a thirst for innovation and desire to modernise every club he touches.

A few minutes into the game, Rangnick had to stop and count the number of opposition players, convinced they were fielding more than 11 because of the suffocating way Dynamo systemically pressed the ball.

"We chanced upon a genius," Rangnick said, with the encounter shaping the high-intensity football the 'Godfather of Gegenpressing' has become renowned for.

Some of the principles the German learned from observing Lobanovsky's side - and Arrigo Sacchi's AC Milan of 1987-1991 - are already being implemented at United's Carrington training ground. Now it is 63-year-old Rangnick whose reputation and unique approach precedes him.

Those who have worked with Rangnick describe a mastermind at building clubs. A man whose emphasis on fine details drives players to their best - but can also be exhausting and push some to their limits.

United's interim boss said it himself last week: "The players have to buy in. I need to get into their heart, their brains, their blood, whatever. The first steps have been taken."

He is said to be someone who challenges the status quo, implementing his own structure as soon as possible. He can be impatient and intense - and ruthless with anyone lagging behind. He demands success and knows how to create a high-performance environment to get it. Although he is unlikely to dictate to Cristiano Ronaldo how to "eat and sleep", as one source put it, he quickly attempts to convince star players of his methods.

His most notable trophy success may seem underwhelming - one German Cup with Schalke a decade ago - but his real craft comes in developing his surroundings. That is his mission at United, a club that appears to have struggled for a clear sense of direction since Sir Alex Ferguson's departure in 2013.

For Rangnick it is a familiar challenge, but the circumstances are quite different to what has come before.

Rangnick's methods have been honed throughout a long coaching career that might be short on silverware but includes three remarkable transformations. At Ulm, at Hoffenheim and at RB Leipzig, he took lower-league clubs and formed them into Bundesliga teams.

Ulm were in the third tier when he arrived in 1997. But by the time he left in 1999 for a bigger job at Stuttgart, they were about to seal a place in the German top flight for the first time in their history.

At Hoffenheim, he took over in 2006 and achieved two successive promotions, establishing a structure that has since seen the ambitious club evolve into a Champions League side - they made the group stages in 2018-19.

"Ralf Rangnick is one of the most important architects of TSG Hoffenheim, a football visionary and in a positive way, driven," football director Alexander Rosen tells BBC Sport.

"On one hand, he is able to generate short-term success but above all, he is someone who thinks and plans strategically for the long term."

There have been other roles where Rangnick enjoyed mixed success - at Stuttgart, at Hannover - or just missed out on significant achievement, like at Schalke. In the first of his two spells in Gelsenkirchen, Schalke were beaten to the league title by Bayern Munich in 2004-05. In his second, they reached the 2010-11 Champions League semi-finals, only to suffer a 6-1 aggregate defeat by Manchester United.

But perhaps his best work has come at RB Leipzig.

Ragnick, pictured among Leipzig fans at Borussia Dortmund in 2017, when he was the club's director of football

In 2012, Rangnick was appointed sporting director for the two European sides owned by Red Bull - Red Bull Salzburg and RB Leipzig. Here he had an opportunity - as at Hoffenheim - to exert maximum influence, backed with the resources to achieve his vision.

Alexander Zorniger was the man chosen to take charge at Leipzig by Rangnick, who sold him the project during an intense four-hour chat. Soon, 7am phone calls would become the norm.

"Ralf hates wasting time - he wants to make the next steps," Zorniger tells BBC Sport. "If someone is thinking right now in Manchester United 'well, it will take three or four years and then you will see the first influence', no chance. If people are not doing what he expects, then he will replace them.

"He is the most improving professional I ever met. Every day he is checking everything: 'Is that still state of the art? Do we need to improve something?'

"He always says football is a picture with 100 puzzle pieces and we should be able to provide all the 100 pieces to the players to become better players. That is what he is doing regarding nutrition, mental preparation, physical needs, physiotherapy, even checking hand-eye coordination, kinetics."

The recently formed RB Leipzig were still trying to get out of the fourth-tier Regionalliga Nord when Rangnick arrived. Within four years, they were competing in the Bundesliga.

It was Zorniger who guided Die Roten Bullen to successive promotions before Rangnick took the coaching reins to complete the club's rise with a second-place finish in the second division in 2015-16.

"Rangnick is the architect. He is a great man, he did all of this," says Guido Schafer, who charted RB Leipzig's rise as chief reporter at the Leipziger Volkszeitung.

"When he arrived at Leipzig, everything changed. He made the club younger, faster. It's his philosophy and since this day everything is under the pressure of this philosophy."

Rangnick, pictured in 2008, when he was Hoffenheim manager

Innovative ideas included a countdown clock in training that allows players eight seconds to win the ball back and 10 to score a goal. Sleep experts were brought in, as was a Soccerbot machine

that simulates previous matches to help players improve their cognitive ability.

Rangnick believes in "developing quicker minds rather than quicker feet" and would demand players arrive 90 minutes before training to undergo tests that allow staff to know how hard and for how long they should exercise that day.

"Ralf is not just a coach, he's also like a psychologist," former Hoffenheim striker Chinedu Obasi told BBC World Service. "He knows how to get the best out of his players, he knows how to demand it and he expects you to do it."

It was at Hoffenheim that Rangnick first began looking to younger players. He believed they were better suited to his high-energy football as they would recover more quickly, and have empty 'hard drives' free of ingrained habits that are hard to coach out.

"Ralf is an advocate of innovation in sport - he wants to break down old ideas to unleash new energy in a club," adds Hoffenheim's Rosen.

"He also has a good eye in the scouting department. To identify, acquire and nurture young talent is one of his greatest strengths."

Rangnick's approach was furthered across Red Bull's global portfolio of clubs - including New York Red Bulls and Red Bull Brasil. There was a policy of generally only signing players aged 23 or under from a database that has developed to include more than 400,000 footballers, ranked by specific personality traits and characteristics.

"Ralf Rangnick is an absolute football expert and a gifted club builder," says Leipzig chief executive Oliver Mintzlaff. "We have a lot to thank him for. Without him we would not have been able to achieve the success we have had in recent years."

When Rangnick resigned from his role with Red Bull in the summer of 2020, RB Leipzig were firmly established among Germany's elite. That Covid-affected season saw them reach the Champions League semi-finals, losing to Paris St-Germain, and finish third in the Bundesliga.

He has talked about success hinging on three Cs - concept, competence and capital. At Hoffenheim and with Red Bull's teams he found all three, with money and a blank canvas on which to work.

Circumstances at Old Trafford are different.

Rangnick has two wins and one draw from his first three matches with United

"Ralf has always had the possibility to change everything," says Zorniger. "In Hoffenheim and Leipzig, he implemented a new coaching team, new players, a new medical department, a new scouting team.

"He doesn't have these possibilities right now in Manchester United. These old, traditional clubs, they have an old, difficult network - and to open up and create new structures can be something really difficult.

"When he was appointed manager of Stuttgart in 1999, that was the first time he had to manage big players, and he was struggling because they didn't follow everything he thought might be a good idea. But he has more experience as a coach now and knows exactly where he can change things immediately and where it takes a little while."

At Hoffenheim and RB Leipzig, Rangnick was able to get the early process up and running efficiently. His ideas could be implemented quickly following conversations with the club owners - Dietmar Hopp at Hoffenheim and Dietrich Mateschitz at Leipzig.

"When something made sense, we did it," explains Zorniger. "It was not like in a normal club, going through a board and discussing it with the financial guys and this guy and that guy.

"That was always the reason Ralf didn't take over every club - he needs to find the perfect situation for his understanding of football, not discussing with seven former players whether something makes sense or not."

Rangnick, pictured celebrating RB Leipzig's 2016 promotion to the Bundesliga

Regardless of the different circumstances, change at Manchester United is already under way.

On the training ground, Rangnick often takes a hands-on approach at first before delegating to the trusted members of staff he has handpicked, and has previously employed an army of specialists to cover every eventuality.

He has started this process at United, appointing former USA international and ex-New York Red Bulls coach Chris Armas as his assistant and adding another former colleague to the staff in sports psychologist Sascha Lense, who he worked with at Schalke and Leipzig.

Lars Kornetka, however, has opted to stay at Lokomotiv Moscow and replace Rangnick as sporting director, his most recent role before arriving at United. Kornetka became the first video analyst in German football for Rangnick at Hoffenheim before following him to Schalke and later RB Leipzig.

But there has been talk of another old friend, Helmut Gross - Rangnick's mentor and the man he would write coaching manuals with - helping at Old Trafford in some capacity.

Gross was always the man trusted with delivering sessions to Rangnick's coaches to educate them about the pair's philosophy and update them on any new adaptations. At Leipzig, Rangnick wanted that philosophy to run through the entire club and had all the youth teams adopt the same style of play - it was not uncommon to find him watching under-13 games or coaching sessions.

Ultimately, Zorniger believes Manchester United are getting an innovator who has had the biggest influence on coaching and coaches in Germany in the past 20 years.

"When you are open-minded, you can learn every day from him," adds the German, now manager of Cypriot club Apollon Limassol.

"Everything is on the highest possible level and I am quite sure if Ralf gets the time, he will check the club completely and turn it upside down.

"There are so many aspects from the game you never heard of when you are talking with him. You need to be stupid to not listen to what he is saying."