Then the draw at APOEL Nicosia on Tuesday effectively ended Dortmund's Champions League participation after just three match-days. Goals from Dortmund's speedy forwards helped cover weaknesses in defense, and those faults were exposed in games where the likes of Pierre-Emerick Aubameyang and Mario Goetze failed to shine up front.
And that wasn't just in the last week's matches. "You have to be honest and say that we also didn't deliver optimal games before," sporting director Michael Zorc said after the 1-1 draw in Nicosia. "Everything that was going well in the first weeks looks inhibited now."
A mistake from goalkeeper Roman Buerki cost the side in Nicosia. "That happens, and the players have to be there now for Roman," Dortmund coach Peter Bosz said. "You also have players who don't score and others who make mistakes."
Shinji Kagawa struck the crossbar, and Aubameyang could have won it in injury time. It could also have been worse for Dortmund - Sokratis cleared off the line just before Aubameyang's chance. Dortmund's 6-1 rout of Borussia Moenchengladbach on Sept. 23 looked spectacular but the side was fortunate that 'Gladbach didn't make the most of several clear chances.
Real Madrid made more of those defensive frailties in the next game, winning 3-1, as Tottenham Hotspur had done in the sides' opening Champions League game two weeks before. An unimpressive win over Augsburg preceded the 3-2 loss to Leipzig, a game in which Dortmund appeared too comfortable after getting an early goal.
"It's not possible to win every game with super football," said Bosz, who needs to tighten Dortmund's defense after conceding in each of the side's last five games across all competitions. The first of those goals, scored by 'Gladbach in the sixth round, was the first Dortmund conceded in the league.
Bosz already had a tall task on his hands to help the side get over the tumult of Thomas Tuchel's season in charge. Despite winning the German Cup, Tuchel had to go after falling out with club management, and his departure wasn't universally popular among the players.
But the mild-mannered Bosz appears to have won the players to his side. The former Ajax Amsterdam coach favors a spectacular brand of football that sweeps everyone along when it works - but can look naïve when it doesn't.
Bosz has also had to incorporate seven new arrivals after another summer of upheaval at Dortmund; namely Andrey Yarmolenko, Maximilian Philipp, Omer Toprak, Mahmoud Dahoud, Jadon Sancho, Jeremy Toljan and Dan-Axel Zagadou.
Meanwhile, winger Marco Reus is still out after tearing a posterior cruciate ligament in the German Cup final last May. He isn't expected to return until March next year. Talk of a crisis has been dismissed by midfielder Julian Weigl, who received support from Marcel Schmelzer.
"We shouldn't allow ourselves be talked into (a crisis), or acknowledge it even if it is," the Dortmund captain said. "We have to show a reaction at the weekend to get three points and self-confidence."
Dortmund faces two successive away games in the Bundesliga, Eintracht Frankfurt on Saturday and Hannover a week later - with a German Cup second-round match at Magdeburg in between. After them is a potentially decisive game at home to resurgent Bayern Munich on Nov. 4.
"We have to concentrate on the Bundesliga again so that nothing happens to us there, too," Schmelzer said.