At the beginning of December, the pressure on Dortmund coach Peter Bosz is bigger than ever. The Black and Yellows have plummeted from first to fifth place in the Bundesliga after a horrendous streak of six winless matches, including four losses.

The most recent disappointment, an epic Revierderby in which Dortmund blew a 4-0 half-time lead to bitter rivals Schalke to draw 4-4 at full time, has stoked even more speculation about possible coaches that could replace Bosz in the near future.

For now, however, there doesn't seem a feasible replacement and thus Bosz stays in charge. At Sunday's members assembly, Dortmund CEO Hans-Joachim Watzke made clear that he wants to see a turnaround sooner rather than later. "I have the clear expectation, dear Peter, that you and your staff will leave no stone unturned and put everything to the test," Watzke said.

Of course, it will now be harder than ever for Dortmund to turn their form around. Despite salvaging a point in the derby, the match most likely inflicted more damage on the already brittle confidence of Dortmund's players than a timid 2-0 loss may have had. How will the coach and his players ever feel that a lead is safe if a four-goal advantage is seemingly not enough?

The lack of confidence is quickly named when it comes to explaining the current malaise BVB are in by players and coach alike. Confidence, however, is not the only issue at the Westfalenstadion.

"Improvise. Adapt. Overcome." Those are three words by survival specialist Bear Grylls that have become a somewhat popular meme on the internet and that Bosz should take to heart if he wants to survive at the helm of Borussia Dortmund.

There are, of course, many factors that have led to the Ruhr sides's free fall -- though one significant factor in the crises that started in October is Bosz's failure to make successful adjustments within a match.

The 3-2 home loss to RB Leipzig is arguably one of the few examples where the Dutch coach picked the right approach but it lacked execution. In the first half, Dortmund's two centre-backs were pressed far up the field and the passing option to holding midfielder Nuri Sahin was cut off, resulting in an outrageous amount of back passes to goalkeeper Roman Burki. At half-time, Bosz switched to a 3-4-3 and brought on Julian Weigl to address that issue -- though Weigl lost the ball in midfield early in the second half, resulting in a penalty for Leipzig and a red card for Dortmund. After that, the game was out of reach for the hosts.

In the 2-2 draw away to Frankfurt and the 4-2 loss away to Hannover, both coaches Niko Kovac and Andre Breitenreiter respectively applied a heavy man-marking scheme which saw no reaction by Bosz to gain a tactical advantage throughout 90 minutes. Instead, Dortmund's high line was punished while their build-up play was stifled. The 3-1 home loss to Bayern Munich was one of the dullest Klassiker fmatches rom a tactical standpoint with little to no in-game adjustments by either coach.

Dortmund players may be wondering if they can protect any lead after blowing a four-goal advantage to Schalke Alex Grimm/Bongarts/Getty Images

Hannes Wolf also reverted to a man-marking scheme in Dortmund's 2-1 loss away to Stuttgart, leaving BVB's right-back Jeremy Toljan open in the first half. Bosz's side exploited the little space they had and scored a deserved equaliser after a dominant 45 minutes. But Wolf shut down Toljan after the break and Dortmund's dominance vanished. VfB scored the go-ahead goal as Bosz failed to come up with a clever response.

In Saturday's derby, Dortmund had the upper hand at the start. Bosz fielded a 3-4-3 system with Christian Pulisic and Raphael Guerreiro acting as wing-backs. Schalke coach Domenico Tedesco admitted that he was completely taken by surprise by the lineup and the hosts were ruthless to exploit the numerical advantage in midfield.

"We completely destroyed Schalke from a tactical standpoint," Sahin told ESPN FC after the match. Again, there were a lot of factors why Dortmund failed to hold on to a 4-0 lead but after Tedesco made a double-switch in the 32nd minute, bringing on Leon Goretzka and Amine Harit, the dominance of the hosts once again vanished.

"We stopped playing football in the second half," Bosz bemoaned after the match. Bringing on two defenders for midfielders in the final 22 minutes certainly did not help a decimated BVB side to hold on to the ball and circumvent Schalke's pressure.

Dortmund also have an unimpressive track record of individual errors that have led to goals since October to add to their tumble. Though they have conceded 12 of their 18 league goals in the second half and that also has a lot to do with Bosz being outsmarted by his counterparts on regular basis.

On Saturday, Dortmund travel to Bayer Leverkusen, a team that is unbeaten in eight consecutive league games and is on the ascendency under head coach Heiko Herrlich.

"In-game coaching is actually one of Herrlich's strengths," Constantin Eckner of tactics blog Spielverlagerung told ESPN FC. The Rhine Side have scored 17 of their 26 goals in the second half. In a 2-2 draw against Leipzig a fortnight ago, a decimated Leverkusen wrestled back with impressive energy levels to snatch a point.

Dortmund, meanwhile, have looked flat and flustered in the final 30 minutes in every match since the middle of September. Against a confident Leverkusen that don't have to deal with pesky midweek fixtures, one can only fear the worst for Bosz.

It is now on the 54-year-old to pull the right levers to win at the BayArena on Saturday afternoon. Against Schalke, he got his initial tactics right but he needs to raise his in-game coaching if Dortmund want to stand a chance for 90 minutes.

That task won't become any easier with Pierre-Emerick Aubameyang being suspended due to his red card against Schalke and with the best player of the season so far in Mario Gotze ruled out until the end of 2017 with an ankle injury.