"Wir haben es in der Hand!" read the banner across the bottom of the Yellow Wall: we have it in our hands!
Behind it, the famous terrace was an expectant, seething cauldron of color, smoke and deafening noise, and had been since well before kickoff. Even the pre-match warm-up was greeted by a blaze of pyrotechnics.
"Borussia! Borussia! Borussia!" they bellowed, knowing that, for the first time in over a decade, Borussia Dortmund were in control of their own destiny.
Victory at home to Mainz, mid-table and with nothing to play for after losing their last four, would see them crowned Bundesliga champions for the first time since 2012 under Jürgen Klopp, regardless of what Bayern Munich did elsewhere. Having won all of their previous 11 league home games by a combined score of 46-10, it seemed a routine task.
A routine task for Edin Terzic, the head coach who has lived and breathed Borussia Dortmund from the terraces to the touchline. A routine task for Marco Reus, the captain who has battled injury after injury over the course of a long career with his boyhood club. And a particularly routine task for Sebastien Haller, who has overcome challenges of far greater magnitude over the past year.
But it turned out to be beyond them. Mainz took a two-goal lead, Haller missed a penalty and, despite Dortmund pulling two goals back late on, Bayern Munich's 2-1 win in Cologne saw the Bundesliga trophy, the Meisterschale, slip agonizingly from their grasp. And the Yellow Wall fell silent.
Back in August, having taken on the role of permanent head coach, Edin Terzic addressed Borussia Dortmund's supporters in a video message.
"Let us be hungrier than ever before,” he said. "Let us work harder than ever before. Let us be louder than ever before. Then one day, we'll have the chance to celebrate like never before.”
It was an emotional address from a coach who, while younger and less experienced than his predecessors, understands better than anyone the unquantifiable human elements of Borussia Dortmund, a club which generates extreme emotion like perhaps no other in Germany.
Sometimes, it's a hindrance, and the club's inability to move on from the phenomenon that was Jürgen Klopp often made life difficult for his successors, particularly the ultra-technical Lucien Favre and Thomas Tuchel – now a Bundesliga winner with Bayern.
Terzic, however, has black and yellow blood running through his veins, and he's never been afraid to show it, whether being close to tears in April, despairing after his team had twice thrown away a lead against ten-man relegation strugglers VfB Stuttgart, or shaking with rage in Bochum after the video assistant referee inexplicably failed to review a clear foul in the penalty area.
Even during one of the season's high points, Anthony Modeste's injury-time equalizer at home to Bayern in October, as bodies flew left, right and center across the Südtribüne, Terzic looked to the heavens with tears in his eyes. Just a week earlier, his father Ibrisim had passed away, aged 72.
"We need our fans, our city and our region to bring the emotion,” he said after the 3-0 victory away at Augsburg last week which set BVB up for match point on the final day. "We'll deal with the sport.”
Dortmund falter after season of twists and turns
Ultimately, though, they didn't. And, for all his human qualities and identification with the club, Terzic will know he has to take some responsibility.
On Saturday against Mainz, Dortmund were laborious, slow and nervous, unrecognizable from the team which had blown away Cologne (6-1), Eintracht Frankfurt (4-0), Wolfsburg (6-0) and Borussia Mönchengladbach in recent weeks.
The only chance of note from open play before half-time came from a Julian Brandt dribble and shot, which was easily saved. Meanwhile, at the other end, Andreas Hanche-Olsen was allowed to dart in at the near post unopposed to head Mainz into the lead, before Karim Onisiwo evaded veterans Emre Can and Mats Hummels in the box to nod home the second.
It was a throwback to the first half of the season when, admittedly having had their pre-season attacking plans torpedoed by Haller's diagnosis and injuries to Donyell Malen and Karim Adeyemi, Dortmund regularly looked blunt up front as they lost six games.
And there were elements of fortune to the games they won: narrow 1-0 wins over Bayer Leverkusen, Hertha Berlin, Hoffenheim and Schalke – the latter thanks to a late winner from teenage striker Youssoufa Moukoko. Dortmund also had Moukoko and another teenage substitute, Jamie Bynoe-Gittens, to thank for a late comeback in Freiburg (3-1), while Gio Reyna came off the bench to rescue them late on in back-to-back games against Augsburg (4-3) and Mainz (2-1).
They were great individual moments, and testament to Terzic's careful man-management of his squad and his fatherly approach to his youngest players in particular, but they papered over cracks – and Dortmund have ended up paying the price.
The tragic irony is that the player the most responsible for Dortmund's upturn in form in the second half of the season, especially in the final third, ended up the unwilling villain on the final day.
"Seb felt confident, and we trust in Seb,” said Terzic, explaining why Haller had stepped up to take a first-half penalty against Mainz, a chance to bring Dortmund level at 1-1, rather than the designated penalty-taker Can. Goalkeeper Finn Dahmen saved easily.
"Seb has written an incredible story this season,” Terzic insisted. "I didn't doubt him for a second.”
Haller offers perspective
Haller's journey has indeed been incredible, and transcends the result of any football match.
The decibel levels which greeted his first appearance for Dortmund as a substitute during the 4-3 win over Augsburg in January, taking to the field with the words "f*** cancer!” stitched into his boots, were topped only by the roar ahead of kick-off on Saturday.
Two weeks later, on World Cancer Day of all days, he scored his first goal in a 5-1 thrashing of Freiburg. "I felt like I was flying, like I was on a cloud, like the whole stadium was on fire," he said, his delight evident in the plethora of similes in his language.
It still took him a couple of months to hit top form – understandably, having undergone chemotherapy and two operations. But when he did, his timing couldn't have been better, as he netted five goals in Dortmund's final five games, and set up three more.
"If someone had told me six months ago that I'd be in this situation, I wouldn't have believed them,” he told DAZN on the penultimate matchday in Augsburg.
It's a reminder that football really is only a game – albeit a "hard game, a tough game,” in Terzic's words in a melancholy post-match press conference, "a game we have all fallen in love with.”
Moments earlier, he had stood in front of the towering Yellow Wall, tears streaming down his face as over 24,000 fans shouted his name, in love with a coach who thinks like them, celebrates like them and suffers like them. Because he's one of them.
And, as illogical and pyrrhic it may seem on a day like Saturday, that matters in Dortmund, where the silence didn't last long.
"Steh auf! Steh auf!” the Yellow Wall cried at the Dortmund players lying stricken on the turf at full-time – "Stand up! Stand up! Whenever Borussia play, the terrace will stand behind you, so that you're never alone: Borussia BVB …”