"The performances of our team since the start of the season have not met the expectations we had of them," said Bayern Munich’s chief executive Karl-Heinz Rummenigge, his joie de vivre dampened after removing Carlo Ancelotti following September’s 3-0 UEFA Champions League undressing by Paris Saint-Germain. "The game in Paris clearly showed that we had to draw consequences."

Despite having won the 2016/17 Meisterschale, those consequences were clear: Ancelotti and his players were no longer functioning as a unit. The previously unsinkable good ship Bayern had sprung a leak.

Before it sank any further, the club turned to Heynckes, who took charge of the club for a fourth time on Matchday 8 with the team five points behind the early season pacesetters, Dortmund. Appointing the 72-year-old veteran may have looked like a default and desperate choice. Instead, it was one small step back into the game for a man who had been on self-enforced gardening leave since winning the 2012/13 treble, one giant leap for Bayern-kind.

The scale of the transformation under Heynckes is the kind usually only witnessed when fairytale princesses kiss bewitched frogs.

Watch: How Heynckes revitalised Bayern

In the space of 20 league matches, a five-point deficit to Dortmund has been turned into an 18-point advantage. Eighteen! Schalke are Bayern’s closest rivals in that span of games, and even Domenico Tedesco’s regally performing Royal Blues are a speck on the horizon having picked up 13 points fewer. 

What is incredible is that other statistics show only marginal gains under Don Jupp compared with Don Carlo this season: 2.3 goals scored per game for the first, 2.5 for the second; 18 shots on goal and 63 per cent possession on average per game for both; 53 per cent challenges won under the Italian, 54 per cent for the German’s side. 

The impressive difference comes in terms of goals conceded: in the first seven league games of 2017/18, including Willy Sagnol’s Matchday 7 cameo, Bayern conceded on average a goal a game, and Manuel Neuer was in goal for three of those. In 20 matches under Heynckes — with Sven Ulreich between the posts — they have conceded just 13.

Bayern are unrecognisable from the side that were held to successive draws by Wolfsburg and Hertha Berlin prior to Heynckes' reappointment. © imago

How did Heynckes do that?

The rosy-cheeked septuagenarian has a charisma that befits his nickname, 'Osram', after the German lightbulb manufacturer. He visibly lit up Bayern when he walked in the door, switching on a squad that had switched off under Ancelotti. "We did not play as we wanted," the Italian had said after the draw with Wolfsburg on Matchday 6. "We were slow, without intensity and not compact enough." That cannot be said of Heynckes’ side, who have displayed the same ruthless streak that swept them to the treble five years ago. It is like he never went away.

Heynckes’ approach is clear. "I’m a man with feelings and sensitivity," he explained. "But there are rules and standards that one has to stick to. Discipline is important, but still more important is that there is a consensus between the players. That’s the path that we must take here at Schalke."

Yes, you read right: Schalke. Heynckes laid out that ethos when he swapped Athletic Bilbao for Gelsenkirchen in summer 2003. His principles have not changed, but they have changed Bayern.

Heynckes has no trouble communicating his ideas with the Bayern players. © imago / Sven Simon

The squad, many of whom had already worked and — most importantly — won under Heynckes, responded positively to their new boss. Arjen Robben had described former Bayern coach Pep Guardiola as "obsessed" with football, and Heynckes is cut from the same cloth. How can you tell? After promising to retire so many times, and then actually doing it in 2013, Heynckes — aged 72 — still wants to be making decisions from pitchside or in the dressing room, not yelling at his TV from his sofa like the rest of us.

It also put him in a position to make small adjustments, such as telling Kingsley Coman and Joshua Kimmich to hit the brakes slightly before crossing, helping ensure a better end-product from two mightily promising young players, and — in Kimmich’s case — partly limit the damage of Philipp Lahm’s retirement. His ability to speak fluent Spanish, in addition to his peerless man-management skills, have brought the very best out of Arturo Vidal and helped James Rodriguez settle quickly and perform superbly since joining from Real Madrid last summer.

Watch: A closer look at James Rodriguez' storming debut season in the Bundesliga

That quartet have not been the only ones to benefit. Javi Martinez has revelled in his return to a defensive midfield role — the one he excelled in at Athletic before joining Bayern — and has enabled Thiago Alcantara to influence the game in the way Xabi Alonso might have. But perhaps Thomas Müller’s renaissance is the most striking.

The Germany international, who appeared a lost little boy under Ancelotti, has blossomed with Heynckes in charge. With James sitting snugly and quite brilliantly in his preferred central role, Müller has been able to return to his favourite position on the right. All but one of his six goals and ten assists have come since the veteran tactician’s appointment. "There’s not another player like him in Europe," Heynckes gushed recently. Müller, and the rest of the Bayern squad, no doubt say the same thing about their boss.

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