Early this summer, fresh from UEFA Champions League disappointment, things were looking a little bleak for Borussia Dortmund.
Mario Gotze's release clause had been activated and he was joining Bayern Munich, while Robert Lewandowski was widely expected to follow suit.
With two key players seemingly on the way out, an air of doom and gloom descended upon Signal Iduna Park. To make matters even worse, Bayern were in the process of finalising a historic treble-winning campaign by stuffing Stuttgart in the Pokal final.
It looked as though Bayern were slating themselves in for another dominant, uncontested season, but Dortmund general manager Hans-Joachim Watzke finally snapped, deciding enough was enough.
"Lewy" was denied the move to Bavaria he so desperately sought, and the club reinvested Gotze's transfer fee to replenish the attacking options in the side.
Rather than try and replace Gotze in a like-for-like deal (that would have been nearly impossible), Jurgen Klopp chose to change his side's skin and revamp their attacking approach.
The best teams change to stay on top, and BVB were no different in realising this.
Mkhitaryan is one of the most dynamic, expansive and unpredictable No. 10s in the world, and despite some iffy form early on, injuries can be blamed in stifling his game.
He's the type of player who has to be sharp and fit to play well, and we're still a few weeks away from seeing the best of him.
Aubameyang offers something completely different again, and being used on the right-hand side of a 4-2-3-1 formation unlocks his ridiculous acceleration and top-end speed.
While Robert Lewandowski leads the line and occupies the centre-back's attention, Aubameyang can drop off into space, receive the ball and sprint forward. Defensive lines, on the turn, hate nothing more, and when the Gabon international finds a slither of composure, he's going to be a lethal weapon in Klopp's system.
Opposite him resides Marco Reus—the player Aubameyang can aspire to become. Reus is lightning quick, too, but his close control and decision-making process are years ahead of his new colleague's.
With Ilkay Gundogan's playmaking ability, in addition to the presence of Jakub Blaszczykowski and Kevin Grosskreutz, ensures the club will have depth across the forward line.
Historically, Klopp has been fond of changing his tactics on a game-by-game basis, and he frequently moves the "playmaker tag" from player to player in order to ensure his key players aren't marked out of the game.
You'll be hard-pressed to find another squad so capable of playing in so many different ways, and Klopp will feel he has an option for every potential situation he could come across this season.
If BVB want possession, Gundogan can control games from deep with ease. If the club are under pressure, Lewy's status as a complete forward means he's happy to bring long, aerial punts down to ease the pressure. Should they decide to counter at blistering pace, Reus and Aubameyang are physical marvels.
Gotze may have left, but Klopp has bought so cleverly that it's arguable the club is now better off.
The truth is, Borussia Dortmund are now an irresistible, varied and overwhelming attacking force, and it's looking incredibly likely they can take Bayern all the way, both domestically and in Europe.
They've started the season with nine points from nine, but it's clear the new players are still adapting—the overwhelming statistic drawn from their 1-0 win over Werder Bremen on Friday night was that 32 shots were taken on goal, yet only one found the back of the net.
It's been the story of the season so far, and die Schwarzgelben have been haunted by it over the last three weeks. But once this side clicks into gear, there will be few defences in world football capable of stopping them in their tracks.
Statistics via WhoScored?