With 70 minutes played, Dortmund still trailed to two first-half Rafael Santos Borre goals. Substitute Thorgan Hazard kick-started the comeback in the 71st minute, before Jude Bellingham and Mahmoud Dahoud completed the trick in the 87th and 89th minutes respectively.
"The belief returned with the first goal for 2-1," said Dortmund head coach Marco Rose after another thrilling advert for Bundesliga football. "To completely turn a game like that on its head shows the lads the importance of attitude."
It seemed unlikely Dortmund would be speaking so positively about mentality at the final whistle. Despite making a strong start, in which Thomas Meunier saw a vicious effort pushed onto the woodwork by Frankfurt goalkeeper Kevin Trapp, defensive lapses cost BVB two avoidable goals.
Borre stole in to apply the finishing touch to a Filip Kostic free-kick, before taking advantage of Marco Reus's miscued clearance to add a second. The Colombian personified Eintracht's first-half efficiency, putting away two goals with an Expected Goals rating (xG) of 0.3, but Kostic's role should not be underestimated.
The Serbian was a constant thorn in the side of Dortmund, with over half of Eintracht's first-half attacks coming down his preferred left-hand side. BVB right-back Meunier didn't win a single one of his direct duels with the Frankfurt winger, who was involved in both goals, and did his job defensively after that early wobble.
Those defensive frailties notwithstanding, all was not lost for Dortmund. They'd enjoyed 61 percent of possession in the first half, and were even ahead in terms of xG after Donyell Malen struck the upright shortly before the break.
"At half-time, the coach told us to do the things we were doing in the first 15 minutes again," revealed defender Mats Hummels. "He said we'll get chances, we always have the quality to score goals and we have to take charge."
Dortmund continued to see more of the ball after the restart, but initially lacked the necessary cut and thrust in the final third. Frankfurt, meanwhile, spurned a fantastic opportunity to add a third goal when December Rookie of the Month Jesper Lindstrom shot straight at Gregor Kobel in a one-on-one.
It proved a pivotal miss. Dortmund slowly wrestled back the initiative, overtaking Eintracht for distance covered and challenges won. Erling Haaland began to assert himself more and more in the lone striker's role, while the introduction of Hazard for Julian Brandt enabled Reus extra freedom to roam in behind.
Indeed, Reus finished the contest as the most efficient passer of the ball on the pitch (3.2). Frankfurt's best in the same category was midfielder Sebastian Rode (2.59) and it's no coincidence that all three Dortmund goals fell after his 66th-minute withdrawal, as Die Schwarzgelben swarmed the central areas.
Ultimately, Dortmund's individual quality told. It was Reus who pounced on Martin Hinteregger's mistake to feed Haaland in the build-up to Hazard's goal. Haaland freed up space for Bellingham to head in Meunier's inch-perfect cross, and it was his attempted dribble that resulted in Dahoud firing in with unerring accuracy from outside the box.
A win no one saw coming following a disastrous first-half spell, Dortmund never stopped believing as they closed the gap on leaders Bayern Munich to six points. To sustain the charge, Hummels says BVB must show consistency and perform with the same level of intensity over the full 90 minutes, not just in phases, "week in, week out".
They now have their very own mini blueprint to do just that.