Rubbing salt into the wounds, the Yellow-Blacks' conquerors have even added former Dortmund hero Mario Götze to their ranks as well as ex-FC Barcelona coach Pep Guardiola and tiki-taka disciple Thiago Alcantara, but what does all that mean for last term's nearly-rans?
Two for the price of one
Dortmund will be aiming to close the gap on Bayern domestically as well as go as far as possible in the UEFA Champions League. To aid their cause, Jürgen Klopp has brought in two of Europe's hottest prospects in Henrikh Mkhitaryan and Pierre-Emerick Aubameyang from FC Shakhtar Donetsk and AS Saint-Etienne respectively.
The free-flowing duo appears a perfect fit for the Yellow-Black puzzle and have already netted their first goals for the club in preseason. Mkhitaryan, though, the most natural heir to Götze's throne, has since been ruled out with an ankle ligament injury for around four weeks: not the ideal build-up to the campaign by any stretch of the imagination.
One to watch
On the subject of stuttering pre-season preparations, Klopp's men recently came up short in the four-team Telekom Cup, collecting the proverbial bronze medal after salvaging some pride in the wake of their defeat to mini-tournament hosts Borussia Mönchengladbach with a narrow 1-0 victory over Hamburger SV.
Far from being the expected outcome, BVB nevertheless played with trademark organisation and effortless fluidity. 21-year-old Jonas Hofmann, for one, seized his moment in the sun, helping himself to the winning goal against Hamburg as well as some post-match kudos from sporting director Michael Zorc. "Outstanding," he surmised.
In the shadows
So life post-Götze isn't so shabby after all. Exciting new faces, a taste for the big time and the vociferous backing of the infamous Yellow Wall: Klopp has everything at his disposal to match whatever treble-winning Bayern throw at him.
Dortmund have lived in those imposing red shadows on plenty of occasions down the years, each time emerging bigger and better than ever before - and there is no reason why that won't be the case again. Write them off at your peril.