Peter Bosz's introduction to life as a Bundesliga coach couldn't have gone any better. Seven matches into last season, his Borussia Dortmund team had blitzed through opponents with a rampaging swagger that produced six wins and 21 goals.

The admirers were clamouring over each other to spurt forth gushing praise for this adventurous tactician of the Johan Cruyff mould.

Now, on his return to Dortmund as coach of Bayer Leverkusen, he boasts an equally free-scoring record of 13 goals and four wins from five. But the admirers are remaining tight-lipped and cautious this time around, and for good reason, too.

Dortmund's spectacular collapse under Bosz is still very fresh in the minds of Bundesliga followers, one which saw that seven-game unbeaten streak turn into an eight-match winless rut and Bosz duly sacked.

The Dutchman's one-minded attacking mindset lacked a sensible defensive structure and it backfired spectacularly. As a result, many skeptics remain unconvinced that the Bayer Leverkusen Peter Bosz isn't just a Dortmund 2.0.

A balancing act

The signs of a replica production are certainly there. The high defensive line remains, the gung-ho pressing game is still a feature, and his use of just one defensive midfielder has been on full display as he's tried to cram all of Leverkusen's attacking weapons into one line-up.

So far, it's largely worked. The positives have outweighed the negatives, with an average of 65% ball possession, 86% passing accuracy and 16 shots per game turning Leverkusen back into an attacking force. Thursday night's exit from the Europa League at the hands of Krasnodar on away goals cannot be blamed on defensive fragility alone. 

Julian Brandt, moved to a central position from the wing, has excelled under Bosz's guidance with three assists and three goals this year, while partner-in-crime Kai Havertz has continued his hot form with three goals too. Playing behind a front three, it's a salivating attacking lineup. Even Leon Bailey is performing again. 

Midfield destroyer Charles Aranguiz, the type of player Bosz lacked in Dortmund, is doing an exceptional job at clearing up the mess that such an attacking team inevitably leaves behind. But how long will it take before the holes start emerging?

"The time in Dortmund was good for him. He has a clear game strategy, but now in a refined framework,” said Leverkusen sporting director Rudi Völler.

In Dortmund Bosz lost the dressing room's trust after his tactics fell flat, and he'll need to ensure his current squad remains on the same page if he's to prove himself as a new, improved coach.

New or old Bosz?

For all the talk of Bosz learning his lessons, it's yet to be proven. Leverkusen still look on the brink of defensive collapse at times and exits from the German Cup and Europa League have muddied the promising start in the league.

"We have not played at the same level of recent weeks," Bosz admitted following the 1-1 draw with Krasnodar. "Our pace with the ball was far too slow. We need to recover as soon as possible, look ahead and learn from the mistakes."

Ironically, that recovery starts in Dortmund, 470 days after Bosz was turfed out. The 55-year-old will be out to prove that his all-out-attack brand of football can triumph over Lucien Favre's more refined brand that has propelled the Black and Yellows to the top of the Bundesliga.

Dortmund need answers

But it's not all rosy in Dortmund, either. Five games without a win, an early exit from the German Cup and almost certain elimination from the Champions League has them treading on shaky ground.

A suspect defense has been accompanied by a toothless attack in recent weeks, which has seen title rivals Bayern Munich close what was once a nine-point gap into a three-point deficit. The club are remaining patient, even if the fans are desperate for a trophy.

"Since the summer and the announced reboot we have faithfully repeated that this young team will also have setbacks, " chief executive Hans-Joachim Watzke told the Bild newspaper.

"The current drop [in form] only seems high because of the strong performance in the first half of the season."

Injuries to first-teamers such as captain Marco Reus, Paco Alcacer, Lukasz Piszczek and Manuel Akanji have not helped, but Favre needs to find a solution, and quick. Jolting out of this mini-blip is essential if Dortmund are to avoid a full-blown crisis and revive their title credentials.

The last thing they need is the return of a scorned ex-coach looking to prove a point with his new attacking arsenal. Dortmund are wounded and Bosz will be going for the kill. But if there's one thing they have, it's inside information.

If Bosz truly hasn't learnt from his mistakes in Dortmund, his former club should be able to take full advantage.

Elsewhere on Matchday 23

- Bayern Munich will look to put pressure on Dortmund on Saturday as they welcome Hertha Berlin. A defeat in Berlin earlier in the season came amid the club's mini crisis, and Niko Kovac will be looking to avoid any similar slip-ups.

- Schalke came within minutes of a shock win against Manchester City in the Champions League, but an encouraging performance bodes well for the rest of the season - if they take advantage of the positives. They travel to Mainz, who have extended coach Sandro Schwarz's contract despite a three-game losing streak.

- Four clear relegation candidates are beginning to emerge with Nuremberg leading the losing pack of Hannover, Stuttgart and Augsburg. The "Club" face Fortuna Düsseldorf, who have dragged themselves out of the danger zone with five wins in their last eight. This match could be defining for both clubs and Nuremberg are on a high after that goalless draw with Dortmund.

Matchday 23 Fixtures

Werder Bremen vs. Stuttgart (Friday, 20:30 CET)

Freiburg vs. Augsburg (Saturday, 15:30)
Bayern Munich vs. Hertha Berlin
Borussia Mönchengladbach vs. Wolfsburg
Mainz vs. Schalke
Fortuna Düsseldorf vs. Nuremberg (Saturday, 18:30)

Hannover vs. Eintracht Frankfurt (Sunday, 15:30)
Borussia Dortmund vs. Bayer Leverkusen (Sunday, 18:00)

RB Leipzig vs. Hoffenheim (Monday, 20:30)

(AFP)