He has been described “as a gift from the heavens” by the former Bayern Munich manager Ottmar Hitzfeld and as “a future all-time best in the club’s history” by the current coach, Pep Guardiola. On top of that, a heap of injuries since the winter break have arguably made David Alaba the most crucial player in the Bavarian club’s campaign to win the Champions League, too.

The World Cup winners Jérome Boateng (adductor) and Javier Martínez (knee) are out of contention for a few more weeks, Holger Badstuber is nursing a broken leg, the Moroccan Mehdi Benatia has only just returned to fitness after a lengthy lay-off. The responsibility to make Bayern’s notoriously high line work and to provide the platform for their uncompromising attacking game has thus fallen on Alaba, who had never played as a centre-back before this season.

Fortunately for Guardiola, the Austria international has excelled in the unfamiliar role with customary athleticism and application. After starting out as a midfielder and getting converted into one of the world’s best left-backs by Louis van Gaal in 2010, the makeshift centre-back has turned defensive leader, leaving his manager lost for words. “He’s just incredible, he’s just … wow,” the Spaniard exclaimed a couple of weeks ago. “He can play absolutely everywhere.”

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It is fair to say Alaba wears his new‑found importance very lightly. As he ambles into the small interview room at Munich’s Säbener Strasse in a plain black T-shirt and trainers, Alaba is unassuming to the point of being shy, a little at odds with his reputation as a social-media prankster – his oeuvre contains a series of shots of the midfielder Franck Ribéry dozing and a nearly-nude double-selfie with his former team-mate Mitchell Weiser, in thongs – and as a typically Viennese lausbub (rascal) who once told the club’s former president Uli Hoeness that he had to “think about” an allegation by a concerned member of the public that he was painting the town red with Ribéry in Munich. “It must have been different black guy, herr präsident,” Alaba told Hoeness the next day.

Still only 23, he talks matter-of-factly of the challenge of facing the Italian champions, Juventus, in the second leg of the last‑16 round on Wednesday (“they’ve shown that they’re a great side with great players, they almost leave no gaps in defence and can attack very well – it’ll be very hard”) but becomes much more animated when the conversation turns to music.

“I love listening to hip-hop and going to concerts with Jérôme Boateng; it’s my hobby,” he says, his eyes lighting up. His Nigeria-born father, George, works as a DJ in the Austrian capital and had a minor dance hit with Indian Song (Two in One) in 1997. But unlike his younger sister Rosemaie, David has no ambition to release records. “I’m better on the pitch than with the microphone,” he says. A YouTube video of him singing R Kelly’s I Believe I Can Fly in a car with the former Liverpool winger Ryan Babel – they were Hoffenheim team-mates when Alaba was on loan there in 2011 – suggests he is probably right.

Bayern knew they had signed “one of Europe’s best young talents” in 2008, when a sightseeing tour of the academy and the city convinced Alaba to opt for Munich rather than several Premier League clubs. As a kid he idolised Patrick Vieira and dreamt of playing for Arsenal.

But even the club are astonished by the player’s development into a master of all trades. He runs all day – “I started jogging with my dad when I was five years old” – he is a fine passer, a precise tackler and pretty good when it comes to free-kicks, too. Few players are as versatile, fewer still are so outstanding in so many different ways, irrespective of the job they are being asked to do. No wonder Bayern are trying hard to tie him down to a contract beyond 2018.

Alaba is adamant that the credit for his emergence as a football universalist does not lie so much with him as with Guardiola. “He pushes everybody, every day, in a good way,” he says. “Especially me. I’ve been getting better with every year he’s been here, because of him. But I didn’t know myself that I could play as central defender.”

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Guardiola did, however. The Catalan has fielded Alaba as a central midfielder, winger, as an orthodox left-back and – in one of his major tactical innovations in Germany – as an advanced, inside left-back pushing into midfield, sometimes in the same game, and has never found him wanting. “I’ve yet to understand what position Alaba played tonight,” the 1982 World Cup winner and TV pundit Paolo Rossi said after Bayern’s 7-1 destruction of Roma in October 2014.

“The coach is very demanding but it’s really amazing to train with him,” says Alaba. “It’s like he reinvented football. He thinks about football 24 hours a day, he’s always explaining to us on the screen what’s the best way to attack, best way to defend, the best way to play with the ball. Now that he’s here in his third year, we understand him better as well. We wouldn’t be as successful without him. He’s given us the best tools – you can see it in our game. His detailed preparation makes it easier for us to beat opponents. And to beat them better as well.”

Guardiola’s obsessive methods and Bayern’s squad depth have put them on course for a fourth successive Bundesliga title, and they will be second favourites, behind Barcelona, to win the Champions League if they can finish the job against Juve, where they got a 2-2 draw in the first leg.

The announcement of the manager’s departure at the end of the season could have been handled differently – the team were somewhat disappointed that he did not tell them in person he was off to Manchester City – but Alaba coolly dismisses the suggestion their season could be affected as a consequence. “We have goals and dreams that we work very hard for to achieve,” he says. “We don’t have a lot of space in our heads to worry about other things.” It goes without saying for him that personal preferences, too, must be subordinated. “I’ll play wherever I can help the team,” Alaba shrugs, with a knowing lausbub smile.

Because he does just that.