DORTMUND, Germany — The home fans poured over the bridge from the city center toward Westfalenstadion, a wave of black coats and hooped scarves crashing into sausage shacks and beer kiosks. Finally, they arrived at the famed Südtribüne, the terraced stand at the south end of the stadium, which rises like a tilted baking sheet and clumps together some 25,000 spectators in what is known throughout soccer as the Yellow Wall.

The singing and chanting started in earnest when Borussia Dortmund’s goalkeepers appeared for their pregame warm-ups (an event generally greeted elsewhere with ambivalence, if not complete ignorance). The stadium was in full throat by kickoff, the 80,000 fans, led by the Yellow Wall, shrieking and shouting as if this were a World Cup final instead of a league game against Mainz, a middling team from western Germany. They sang “You’ll Never Walk Alone.” They sang things far less polite.

And then, suddenly, there was silence. Fifty-two seconds after the game began, Mainz’s Elkin Soto lofted the ball over Dortmund’s goalkeeper and into the net from 25 yards. The place went quiet, understandably. But seconds later, even before play had restarted, the noise returned, even louder than before. In a season of gut punches, the fans seemed to be saying, What’s one more?

“It is like my girlfriend,” said Jan-Henrik Gruszecki, a longtime season-ticket holder. “I have a big fight with her; I am disappointed with her; I am gutted by her. But then, always, I realize that I love her and I want to be with her and I can’t imagine anything else.”