Long admired by those in the know for their technical audacity and relentless enthusiasm, last night witnessed the moment when Juergen Klopp's dashing band of youngsters proved they are more than a mere concept or a trend at continental level. Dortmund definitively made the crossover, demonstrating they have the substance to actually go and win the Champions League.
How else to assess a night when the recently deposed Bundesliga champions scored twice in injury time to turn a 2-1 aggregate defeat into a most sensational 3-2 win over Malaga to take their place in the last four of Europe's elite competition?
This was not Dortmund's signature performance, but it may have been their signature result. Klopp was happy to admit that if Dortmund play as they did against a desperately unlucky Malaga they will have little chance of winning the competition for the first time since 1997. But the manner of Dortmund's victory was more significant than the quality of their display.
Ordinary teams cannot do what Dortmund did in injury time in front of their febrile fans at Signal Iduna Park and turn a big Champions League tie on its head in such fashion. Ordinary teams cannot score twice in added time to completely transform their season in the time it takes to toast a slice of bread.
Yes, Felipe Santana was one of four Dortmund players offside in the build-up to the crucial, final goal. It was clearly a horrendous piece of officiating to let play go on. But Malaga's second was offside too and the fact Santana's effort should not have stood hardly detracted from the drama of the occasion.
Dortmund's ability - exemplified by their sweeping passing moves - has been there for all to see for the past couple of years under Klopp; this was instead a blinding demonstration of their spirit and their resilience.
Marco Reus produced the moment of the night with his sensational backheeled assist for Robert Lewandowski's first half goal - an authentic Dortmund flourish - yet Klopp's men ultimately won this game and kept their participation in Europe alive by resorting to a Plan B: launching long balls in desperation and pounding their opponents with everything they had, refusing to let that Champions League dream die.
Dortmund have been an accomplished side in Germany for some time, a league and cup double last season proved that beyond any doubt, but this was their continental coming of age as they fully delivered on the promise that saw them top a group including Real Madrid, Ajax and Manchester City and then get past Shakhtar Donetsk.
All that good work was about to be wasted, until those illogical added minutes when they summoned up a response worthy of the greatest sides.
Real Madrid and two of Juventus, Bayern Munich, Barcelona and Paris Saint-Germain await in the last four, but to rule out Dortmund after Tuesday night's exploits would be foolhardy. How can you rule out a side that doesn't know when it is beaten?
This was a remarkable 90+ minutes of Champions League action, even managing to overshadow a fixture in Istanbul that for a brief while appeared capable of delivering an even more monumental turnaround as Real Madrid pushed their luck at Galatasaray.
Left needing five after Cristiano Ronaldo's early strike, Gala suddenly conjured up three in quick succession as Emmanuel Eboue scored a scorcher, Wesley Sneijder pulled out a nutmeg and then slotted home and Didier Drogba converted with a quite sublime flick.
But, incredibly, a 20-yard screamer from Eboue that found the top corner of the Madrid net - please do not adjust your computer screen - was not the headline act, not on a night when Dortmund did what they did to Malaga.
So stunning was Dortmund's feat it clearly sent the Spanish club's president spiralling into a brief moment of lunacy. Sheikh Abdullah Al Thani took to Twitter to blame racism - yes, racism - for Malaga's inability to hold onto their two-goal lead at the death, in an unhinged rant that recalled Jose Mourinho's famous diatribe about Unicef.
"Thank you very much for the team you have been Champions On the pitch," he tweeted. "I'm sorry to go out this way injustice and racism. I hope to open a thorough investigation UEFA regarding the Spanish club out this way Which does not affect the spirit of sport. This is not football, but racism and clear of all."
Klopp's reaction was rather more endearing. In his post-match interview the Dortmund coach proved unable to stop bursting into manic laughter, as if Sky were piping nitrous oxide into the tunnel at Signal Iduna Park in industrial quantities. In between giggles that would have befitted a giddy schoolgirl, he described the night's events as "one of the best things I have ever felt."
It was certainly a night for the ages. A team who were once a niche interest, fawned over by football's trendy folk, demonstrated they have what it takes to become part of the establishment.
Perhaps they will fall at the semi-final stage - the quality is certainly going to be extremely high - but now we all know for sure that Dortmund mean serious business in the Champions League.
Tom Adams - @tomEurosport
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QUOTE OF THE DAY
“I will return, almost certainly. What I do not know is when. My daughters and wife still live there. My idea is to train a competitive team. Why not in England? We will have to wait and see. Everything will be worked out.” - Rafa Benitez makes a play for a return to Liverpool at some point in the future. That noise you can hear is Brendan Rodgers furiously scribbling 'Rafa' on a piece of paper and slipping it into one of his famous envelopes.
U-TURN OF THE DAY
9pm: Reading chairman John Madejski says he wants football to mark the death of Margaret Thatcher with a minute's silence at the weekend as it "would be a fitting tribute from the world of football to ... one of our greatest leaders."
11pm: Reading announce on their official website they will be holding a minute's silence ahead of Saturday's game at home to Liverpool, but "as a mark of respect for the anniversary of the Hillsborough disaster."
After the drama of Tuesday night, Wednesday's Champions League fixtures have a lot to live up to. But with Barcelona hosting Paris Saint-Germain and Bayern Munich travelling to Juventus, we could have another superb evening in store.