The treachery, the betrayal, the nerve; how could Mats Hummels do it? Well, there had been those two other guys.
Historically, transfers between Borussia Dortmund and Bayern Munich rarely pass off without controversy – Hummels' low-key 2008 switch from Bavaria to the Ruhr region ironically standing as an exception – and the Germany centre-back's April transfer request prompted a familiar combination of dread and rage among the Dortmund faithful.
The club captain was booed by a significant section of the home crowd during the 5-1 win over Wolfsburg after his intentions became clear.
Bayern prising Dortmund stars Mario Gotze and Robert Lewandowski from their rivals in 2013 and 2014 brought a shuddering end to BVB's magnificent irritation of German football's pre-eminent force under Jurgen Klopp.
The 2010-11 Bundesliga title and the 2011-12 domestic double had Dortmund fans dreaming of a period of dominance that is customarily the domain of Bayern and only Bayern.
Munich then swept the board domestically during Jupp Heynckes' glorious farewell season and, ahead of ultimately beating their Klassiker rivals in the 2013 Champions League final, they landed the body blow.
Gotze, Dortmund's jewel, would join Bayern after a final he missed through injury. Lewandowski made his intentions to do the same clear, although Dortmund squeezed one more season out of the Poland forward at the expense of a transfer fee. They came a distant second to Bayern.
In 2014-15, the first season without both men, they improbably found themselves flirting with relegation midway through the campaign.
The celebrated Klopp moved on having led a recovery to Europa League qualification and, treading the same path as his predecessor from Mainz to Dortmund, Thomas Tuchel took up the reins.
With his own take on a youthful squad flushed with attacking verve, Tuchel rediscovered some of the old Klopp magic and Dortmund stayed in touch to prevent Pep Guardiola's final year in charge of Bayern merely becoming a title procession.
It meant the loss of Hummels to Bayern, along with Ilkay Gundogan and Henrik Mkhitaryan moving to Manchester City and Manchester United respectively felt particularly cruel, with Dortmund apparently crushed once more by financial might at home and abroad.
But the romantics had developed a hard-nosed edge and, against considerable odds, Dortmund enjoyed a close-season in the transfer market that leaves them well-placed to end Bayern's four-year stranglehold on the Bundesliga title.
Firstly, following the experience of hanging on grimly to Lewandowski, Dortmund made sure they were handsomely recompensed for Hummels, Gundogan and Mkhitaryan – men all entering the final year of their contracts.
Hummels' replacement, Marc Bartra, was acquired with the minimum of fuss and expenditure from Barcelona. Stern examinations of the Spain international's defensive expertise surely lie ahead but the manner in which Bartra purred in possession against Bayern in the DFL-Supercup and a DFB Pokal procession versus minnows Eintracht Trier suggest he can stylishly replicate Hummels' capacity to start attacks from deep.
Gundogan's departure might be the most keenly felt, but Sebastian Rode's arrival showed transfers between Bayern and Dortmund can be a two-way street to benefit the latter.
Now 25, having failed to nail down a place during two seasons at the Allianz Arena, Rode is a classy operator entering his prime and could prove a steal for Tuchel, whose most eye-catching changes come in attack.
Gotze is the headline arrival and the prodigal son will have plenty to do if he is to win over all of the fans who once unquestioningly adored him.
The matchwinner in the 2014 World Cup final should have that task made easier by Dortmund retaining Pierre Emerick-Aubameyang – the livewire forward now unquestionably established among the very best in European football.
Andre Schurrle, signed from Wolfsburg, has a point to prove and provides insurance against Marco Reus' fitness struggles, while in Ousmane Dembele and Emre Mor, Tuchel is overseeing two of the continent's foremost attacking proteges.
Renato Sanches' move from Benfica to Bayern gives the champions their own star of tomorrow but Carlo Ancelotti's first close-season in charge has proved low key.
The Italian's reputation in the game made him an obvious candidate when the peerless Guardiola elected to move on to Manchester City, and the smart money would be on him to poke and prompt Germany's most talented squad to glory once more.
However, if there is the faintest whiff of stagnation, Tuchel and his hungry, exciting, brilliant side will need no second invitation to pounce.
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