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.
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.
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.
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.
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.
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.
