Borussia Dortmund's shaky defence has been the main concern in the past few weeks. But now their previously electric attack has stuttered too, the Bundesliga title could be slipping from their grasp.
The defining moment from Dortmund's lackluster draw with Nuremberg was not one of Mario Götze's missed chances, the defiance of Christian Mathenia, or indeed the controversial Jadon Sancho penalty appeal.
No, it arrived in the dying moments of the first half when a harmless long ball sailed through the air into Dortmund's defensive zone. Dan-Axel Zagadou, tracking back, completely misjudged the flight of the ball, which landed on the retreating defender's back.
It was a moment of hilarity, an inexplicable error which almost provided Nuremberg a glorious opportunity at goal. And it summed up Dortmund's performance; clueless, disorientated, and, ultimately, lost.
While Dortmund's defense has rightly been the source of angst amongst fans and journalists trying to correctly predict this season's Bundesliga champion, it was the attack which shone blindingly as the latest red light.
The Dortmund machine appears to be falling apart, bit by bit, one loose screw at a time.
Nuremberg had conceded 46 goals in 21 matches leading into this match and they appeared the perfect tonic for a Dortmund side that had lost its drive in recent weeks amid a mini injury crisis. After all, the Black and Yellows are the league top goalscorers with 54 and had hammered their opponents 7-0 with automatic precision back in September.
Yes, Dortmund were missing key players on Monday night. Captain Marco Reus was again absent through injury, while Paco Alcacer was only deemed fit enough for the bench. Yet while that might explain a blank against a team such as Tottenham, it's does not justify a breakdown against a flailing Nuremberg.
Of course, Rolls Reus' influence can not be underestimated. He's in the form of his life this season with 13 goals and nine assists from 19 matches. But for an attacking machine such as Dortmund to fall apart as drastically as it did against Nuremberg is unacceptable for an aspiring Bundesliga champion. Only Sancho looked capable of influencing the game's outcome.
The movement was non-existent and where it was present it was suffocating rather than liberating. Nuremberg have to be praised for reacting to coach Michael Köllner's sacking with a resilient defensive display, but Dortmund are better than this. Or should be better.
Götze was guilty of profligacy, Sancho was denied what looked like a clear penalty, and Mathenia did make a string of top-class saves. But the missed chances were not the concern. If you batter an opponent and yet fail to find the net, you can at least fall back on the fact that it just wasn't your day. Dortmund didn't batter Nuremberg, the league's bottom-placed team, and that's on them. They didn't deserve victory.
BVB vehicle needs tune-up
"The opponents are aware of our strengths and are adjusting accordingly. We have to find a solution somehow,” Roman Bürki said on Eurosport.
"But it's difficult at the moment, we don't have the punch and we're often physically inferior.”
Lacking punch is spot on. Nuremberg are just the second Bundesliga club to keep a cleansheet against Dortmund this season. The other? Hannover. The league's two bottom clubs have shut up shop against the league leaders and that's just as concerning as a defence struggling to shut out opponents.
Earlier this season - outside the Hannover clash on Matchday 2 - Dortmund made a point of winning games when they weren't at their best. Favre was able to introduce appropriate changes or the team was able to find a solution amongst themselves. Now they're suffering from a third consecutive league stalemate and a fifth game overall without a win.
The Dortmund vehicle which had previously found a fourth or fifth gear when required is now spluttering and stuttering. And it can't be blamed simply on a lack of parts. This is a severe leakage that is threatening to turn into a blown gasket if Dortmund don't find a quick fix.