Twelve years ago, a 20-year-old centre-half from Augsburg’s reserve team faced a sudden realisation: his chronic knee injury would curtail his fledgling playing career and crush his dream of a successful career as a professional footballer.

But when one door closes another opens and for Julian Nagelsmann, who was scheming his exit plan from a game he wanted to leave behind, it was a chance conversation with his coach that changed the course of his life.

The setting was Augsburg, an imperial city in southern Germany which was an important vessel for the pan-European movement of cultural, artistic, political and economic rebirth known as the Renaissance, that Nagelsmann’s career was born-again.

Weighing up his options after a career-ending knee injury forced him to hang up his boots, Nagelsmann was approached by Thomas Tuchel, the then manager of Augsburg’s second team, who offered him an opportunity to join the club’s set-up as a scout.

“Of course I’m very grateful to him for giving me the idea of becoming a coach”
- Julian Nagelsmann

“I still had a contract with Augsburg and that’s why Thomas approached me,” Nagelsmann told spox.de.

“Of course I’m very grateful to him for, let’s say, giving me the idea of becoming a coach.”

The meeting set in motion a remarkable managerial career. Aged 28 he became the youngest manager in Bundesliga history with Hoffenheim. Five years later, he is the youngest in history to coach a side in the last four of the Champions League.

Two years as a coach of 1860 Munich’s U17 side – on the recommendation of Bayern Munich legend Uli Hoeneß – primed him for a switch to Hoffenheim, a nouveau riche club in a southwestern village of barely 4,000 people.

He rose through the ranks at Hoffenheim. Drafted in as an assistant coach to the U17 team in 2012, it took only 18 months for him to join the first-team coaching staff (where he was given the ‘Baby Mourinho’ nickname by German international goalkeeper Tim Wiese).

If Hoffenheim’s rise from ninth-tier amateurs to the Bundesliga was swift, Nagelsmann’s ascent was meteoric.

His impact as first-team coach was instant. Hoffenheim were 17th in the table, seven points from safety when he took over in February 2016. He guided them to seven wins in their remaining 14 games and a 15th place finished, one place above the relegation play-off spot.

The resurgence continued into in the 2016-17 Bundesliga season where they finished fourth and qualified for the Champions League for the first time in their history.

Germany’s youngest coach was quickly becoming one of the most sought-after properties in Europe and it was RB Leipzig, a club who themselves had enjoyed a surge up the German pyramid at breakneck speed, who snapped him up in 2019.

They briefly threatened to challenge for the league title last season but it is in the Champions League that Nagelsmann has proved his worth once again.

After topping their group, Leipzig toppled last season’s runners-up Tottenham 4-0 on aggregate. Nagelsmann became the youngest coach in history to win a Champions League knockout tie and in a moment of symbolic significance, he outwitted Jose Mourinho, the man who he was compared to as an up-and-coming coach. 

A daunting step up against a gnarly Atletico Madrid was next. Undeterred, 21-year-old American fired Leipzig, in their 11th year of existence, into uncharted waters. For their prodigious coach, it was another tactical victory over one of Europe’s most lionised managers.

Quick to dismiss the manager vs manager narrative, Nagelsmann instead praised his team’s collective unity. “The team as a whole beat Tottenham before and now Atletico. It’s not about duels between coaches – not against Mourinho, not against Simeone and now not against Thomas Tuchel either. It is a team game and the guys did brilliantly today,” he said.

The Champions League is a well-trodden path for the brightest young managers to showcase their ability and announce themselves to the world and Nagelsmann is the latest to take the competition by storm after a masterminding a remarkable run.

Next up on Leipzig’s fairy-tale tour of Europe are Paris Saint-Germain and a reunion between Nagelsmann and Tuchel.

Tuchel went onto to work at Mainz and Dortmund after leaving Augsburg and is now tasked with securing a first Champions League win for PSG – a goal that looked to be slipping away against Atalanta in the quarter-final before Marquinhos and Eric Maxim Choupo-Moting spared their blushes.

Nagelsmann has described his relationship with Tuchel as purely pragmatic. “Since Augsburg were still paying me, I spotted opponents for Tuchel,” he said. They have “never been extremely close,” he added.

For Tuchel, he would never have envisaged a meeting with the man he encouraged to take up coaching all those years ago.

“I could not imagine that 12 years after coaching him I would be going up against him in the semi-final,” he said.

“We did not have enough staff and as he was injured we asked him to do some scouting. In my life, I do not project towards the future so at the time I did not think that one day I would face up against him. It is incredible to play a Champions League semi-final against Julian [Nagelsmann].”

Both managers are leading the charge of German managers in Europe. In a noteworthy subplot, three of the four remaining managers in the Champions League are German: Nagelsmann, Tuchel and Bayern Munich’s Hansi Flick. Last season’s winning manager, Jurgen Klopp, is also German.

Had an unlikely series of events played out differently, the prognosis could have been very different.

Watch RB Leipzig v Paris Saint-Germain from 7pm on BT Sport 1 HD, Ultimate and online tonight.