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Opposition fans frequently display banners stating their opposition to Red Bull's backing of RB Leipzig

"It 'gives you wings…'," founder and chief executive Dietrich Mateschitz once said of his Red Bull dynasty, referencing the brand's global advertising slogan.

Mateschitz was not talking specifically about the energy drink on which his fortune is built, but the philosophy which embodies his now-multiplatform, multinational, multi-billion dollar company.

"It provides skills, abilities, power to achieve whatever you want," added the Austrian, who has created an environment that encourages innovative minds and ideas.

RB Leipzig, and 33-year-old head coach Julian Nagelsmann, are a case in point.

Only a decade ago they were making their debut in the fifth tier of German football - on Thursday, they play in the Champions League quarter-finals for the first time.

But it has taken more than Red Bull throwing money at the project for the east German club to establish themselves among the country's elite.

When Nagelsmann's side beat Tottenham Hotspur in the last 16 it was with a team thin on household names and containing no player acquired for more than £20m.

So how did Red Bull turn a club playing regional football into genuine Bundesliga title contenders (they pushed champions Bayern Munich before eventually finishing third), what is in it for one of the world's most well-renowned companies and are Leipzig really the most hated club in Germany?

How it all began for Red Bull in Germany

Few in Germany were open to the idea of Red Bull chief Mateschitz bankrolling a club when it was first touted in 2006, and initial plans to invest in a different Leipzig side, FC Sachsen Leipzig, were rebuffed by the German football association, the DFB.

Fan protests followed as Red Bull explored potential takeovers at St Pauli, 1860 Munich and Fortuna Dusseldorf, before reverting to the initial plan of acquiring a Leipzig-based team.

The historical landscape of football in Leipzig is complicated, with a number of clubs having formed and disbanded since the founding of the DFB in the city in 1900. The Nazi regime, communist rule and subsequent reunification of Germany also led to varying league formats.

FC Lokomotive Leipzig enjoyed success before the reunification, losing to Ajax in the 1987 European Cup Winners' Cup final, but, after a rebrand as VfB Leipzig, their relegation from the Bundesliga in 1994 spelled an end to the city's representation in the German top flight.

Until Red Bull purchased the playing licence of fifth-tier SSV Markranstadt.

Before the rebranded RB Leipzig even kicked a ball in the 2009-10 season there was outcry in Germany, but it was nothing the company had not experienced before.

Many supporters felt alienated when Red Bull acquired Austrian top-flight side SV Austria Salzburg in 2005 and changed their name to Red Bull Salzburg, plus the club badge, staff and kit colour.

In Germany - after years of research and negotiations - they decided to start from the bottom and work up.

A new team in Markranstadt - SSV Markranstadt, in red - continue to play at the Stadion am Bad. They play in the Landesklasse Nord - a regional league on the seventh tier of Germany's football pyramid. In this February match, the official attendance was 30.

By the time RB Leipzig reached the Bundesliga in 2016 the city had been without a top-flight team for 22 years and there had been no side from the former East Germany in the division since Energie Cottbus were relegated in 2009.

That open market presented an opportunity.

"It is good for the city, good for the eastern part of Germany," Guido Schafer, who has charted RB's rise as chief reporter at the Leipziger Volkszeitung, tells BBC Sport.

"The whole city loves RB Leipzig - apart from the two traditional clubs, Chemie and Lok Leipzig - and everyone knows how worthwhile it is to have such a club in the city.

"The fanbase is also growing. Now nearly every match is sold out with 40,000."

That love for the Red Bull-backed club is not shared across the country, and even in their inaugural season RB Leipzig faced a backlash from opposition supporters.

DFB laws state German clubs must operate on a "50+1" rule, meaning members - essentially fans - own the majority of shares and can influence decisions such as ticket prices.

Rivals feel RB Leipzig exploited the system by having just 17 members with voting rights - most are directly linked to Red Bull - and got around a law stating teams must not be named after sponsors by officially calling the club RasenBallsport Leipzig, which translates as LawnBallsport Leipzig.

RB are often referred to as the "most hated club in Germany" and still face regular protests from opposition fans, ranging from boycotting games to the arrest of 28 Borussia Dortmund fans for throwing cans and stones at rival supporters in 2017.

The dislike goes further. Speaking to BBC World Service when Leipzig were first promoted, Dortmund CEO Hans-Joachim Watzke called RB "a club built to push up the revenues for Red Bull" while earlier this month German football magazine 11 Freunde refused to cover the top-of-the-table fixture with Bayern Munich, whose supporters brandished offensive placards.

But Schafer is confident Leipzig and boss Nagelsmann, someone he labels "a genius", are winning people over with their attractive football and intense, high-tempo, pressing game.

"There were some protests, especially from Dortmund, Augsburg and Union Berlin fans, but in Germany and in Europe the respect is growing every day," he explains.

"It's a very good situation for Leipzig and also for the football in Germany that they are at this standard now."

RB Leipzig's new players pose for a photo before training in July 2009 - the reformed club's first pre-season

The house that Ralf built

The Red Bulls have certainly, ahem, flown up the German league pyramid.

Four promotions saw RB Leipzig reach the Bundesliga within eight years of their formation.

This might not have been Red Bull's first foray into football, but it was just the project with the potential to shake things up in one of the game's traditional powerhouses.

After acquiring SSV Markranstadt, an Oberliga team based a few miles from Leipzig, it gave them the full Red Bull makeover, adding it to a portfolio that now also includes Red Bull Salzburg, New York Red Bulls, Red Bull Brasil and several feeder clubs.

Promotion swiftly followed but, with Mateschitz's interference and haphazard hiring and firing, RB found it more difficult to escape the fourth-tier Regionalliga Nord. Until the arrival of Ralf Rangnick.

"Everything started with Ralf Rangnick in 2012," says Schafer.

Rangnick was brought in by head of global football and former Liverpool manager Gerard Houllier, himself sold on joining the Red Bull project after a four-hour meeting with Mateschitz in Salzburg earlier that year and the person credited with bringing forward Sadio Mane, now at Liverpool, to Red Bull Salzburg.

Ex-Schalke and Hoffenheim boss Rangnick was appointed sporting director of both RB Leipzig and Red Bull Salzburg and successive promotions followed.

Rangnick then took to the dugout himself in 2015 to complete Leipzig's climb to the Bundesliga.

"Rangnick is the architect. He is a great man, he did all of this," Schafer continues.

"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 has twice taken the reins when Leipzig were between managers and, after appointing Nagelsmann, held a wider role in the Red Bull project as head of sport and development, until last month.

The 62-year-old's stock in the game is such that he looked set to join European giants AC Milan to rebuild the Serie A club and implement the strategy that has proved so successful at Red Bull. However, that deal never materialised.

Rangnick chose Markus Krosche, who spent the majority of his career playing in the second division for Paderborn, to succeed him as sporting director at Leipzig when he moved positions at Red Bull.

Krosche's sole focus is continuing to build on Leipzig's success.

"We are happy that we have great support by our sponsor, like other clubs certainly as well," the 39-year-old tells BBC Sport.

"Of course, we regularly exchange ideas with Red Bull and its supported clubs in New York and Brazil. But at the same time, we believe that we can create something unique here in Leipzig, creating our own identity."

Finding and developing 'the stars of tomorrow'

Sporting director Markus Krosche (right) speaks to RB Leipzig CEO Oliver Mintzlaff

Rangnick decided on a style of play RB Leipzig wished to pursue and then scouted and signed players to fulfil those requirements - all exclusively 23 or younger, all keen to develop.

"We are looking for young, talented and hungry players," explains Krosche.

"We are not willing to pay an enormous amount of money for so-called football stars, we want to find and develop the stars of tomorrow."

Naby Keita, signed from Red Bull Salzburg, is the club's record signing at £27m and has since been sold to Liverpool for a £21m profit.

Other cstars such as Germany forward Timo Werner, who has now joined Chelsea, was bought from relegated Stuttgart in 2016, Sweden winger Emil Forsberg joined from Malmo when in the second division and Austria winger Marcel Sabitzer arrived from Rapid Vienna before spending a season on loan at Red Bull Salzburg.

Keita, though, is perhaps the best example of how Red Bull's portfolio of clubs provides a global scouting network and inter-club framework in which players can progress.

It is similar to City Football Group - spearheaded by Manchester City and including clubs across the world such as Girona, New York City FC, Melbourne City and Yokohama Marinos - but arguably with more success at supplying talent to the top of the tree.

James Powell, chief executive at Carteret Capital, says this is beneficial to both realising each club's sporting objectives and making a return on their investment.

Powell calls it a "pyramid of shop windows", showcasing talent at increasing higher levels and adding to their market value.

He says Red Bull's "bespoke, globalised player-trading platform" enables the owners to benefit from smart, efficient player trading.

Head coach Julian Nagelsmann joined RB Leipzig from 1899 Hoffenheim in June 2019

Movement between the clubs is fluid - midfielders Hannes Wolf and Amadou Haidara swapped Salzburg for Leipzig last summer, American Tyler Adams arrived from New York last January and the now-Red Bull Salzburg head coach Jesse Marsch has worked at all three.

Promising centre-back Dayot Upamecano is another on a long list players and staff to have represented more than one of Red Bull's clubs, playing for Salzburg's feeder side FC Liefering before progressing to the first team and then joining Leipzig, but is also an example of another influence - that of former Liverpool boss Houllier.

Schafer says Houllier's contacts in his home country have been key to attracting a number of French players to Leipzig.

Upamecano's centre-back partner is Ibrahima Konate, who signed from Sochaux in 2017, while right-back Nordi Mukiele joined from Montpellier and midfielder Christopher Nkunku from Paris St-Germain. All have represented France at under-21 level.

"We have already proven that we can make players better and help them to take the next step in their career," adds Krosche.

"Especially in today's football, a good scouting system is one of the keys to being successful."

One other recognisable cog in the Red Bull scouting machine was Paul Mitchell, the former Southampton and Tottenham head of recruitment who joined Leipzig in 2018 but has since become sporting director at Monaco.

What's in it for Red Bull?

RB Leipzig moved in 2010 to their current home - the Red Bull Arena (formerly the Zentralstadion, a 43,000-capacity ground built in 2004 and a World Cup venue in 2006). The attendance for their first league match there - in the Regionalliga, Germany's fourth tier - was 4,028. Last season their average was 38,380.

Red Bull ranked 71st on Forbes' most-valuable brand list last year, boasts a brand value of more than £7.6bn and sells almost seven billion cans of energy drink across 171 countries each year.

So what does the company gain from owning football clubs?

Getting eyeballs on the brand is crucial - every club in Red Bull's portfolio carries its logo on their shirt, are kitted out in red, white and yellow, and play at their own Red Bull Arena. RB Leipzig are an advert for Red Bull every time they kick a ball.

The same can be said about the brand's ventures into Formula 1, esports and extreme sports.

Viewers will witness Red Bull cars and drivers across 22 stages of the upcoming F1 season, the company's sponsorship of esports teams and events, such as the Red Bull Dragon Ball FighterZ World Finals, captures the attention of a new, younger demographic while stunts such as the Red Bull Stratos high-altitude diving project, which in 2012 saw Felix Baumgartner jump back to earth from the stratosphere, was watched live by more than nine million YouTube users.

It also sponsors athletes across a wide variety of sports to showcase the brand, with England cricketer and BBC Sports Personality of the Year winner Ben Stokes and Liverpool and England defender Trent Alexander-Arnold among the most high-profile stars on its roster.

"The key is consistent, aggressive marketing by ensuring that the iconic brand is viewed by as many people as possible," says Carteret Group's Powell.

But while brand awareness is a major factor, Red Bull is also benefiting from a series of highly profitable franchises and has achieved genuine success across its sporting ventures.

"This is certainly not a vanity project," adds Powell. "Red Bull has shown themselves to be thought-leaders.

"Its goals are similar to City Football Group, both have established a global pyramidal structure in relation to its player development with each team in the group assisting the other.

"Red Bull appears to have succeeded in developing marketing nuances that set the benchmark for other companies."

What next for RB Leipzig?

Krosche says the club's target at the beginning of the season was to secure a Champions League spot once more, something they achieved after the Bundesliga restarted in June.

They finished third, behind Borussia Dortmund and champions Bayern Munich, who have won eight titles in a row. In fact, the last time Bayern didn't finish top, Leipzig were in the fourth-tier Regionalliga Nord.

Krosche believes Leipzig's run in this season's Champions League shows the club are on the right path.

"We are an ambitious young team that is always hungry for more," adds the former midfielder.

"Success never comes too early. We wanted to reach the knockout stages and we succeeded. That was a huge step in our development.

"We definitely don't say our way is the best. There are many different ways to be successful.

"We just believe in our way and we do think there is still more to come."

A version of this article was originally published in February 2020.