Munich - Borussia Dortmund found out the hard way that all good things must come to an end eventually in Sunday's Klassiker.

Die Schwarz-Gelben travelled to FC Bayern München's Allianz Arena unbeaten in 14 matches in all competitions under Thomas Tuchel, only to be, by their own admission, blown away in a chastening 5-1 defeat.

© gettyimages / Alex Grimm

Second best

"It's not what we envisaged at all," admitted Tuchel after ending up on the losing side for the first time since replacing Jürgen Klopp in the BVB dugout in the summer. "We prepared for the game and came here to win. We have to accept that we didn't do that and were beaten comprehensively."

Dortmund started brightly enough, limiting the amount of time Bayern's vast ranks of match-winners had on the ball before striking hard and fast on the break. "But even when we had good spells, we weren't able to cause them any real problems," conceded Tuchel. "They either got men behind the ball or we made the wrong decision."

© gettyimages / Alexander Hassenstein

'Bayern deserved to win'

BVB changed to a more attack-minded 4-3-3 formation shortly after Robert Lewandowski had made it 3-1, but by then the result was already beyond any doubt. Dortmund's experimental back four - with Sokratis and Lukasz Piszczek moved out onto the right- and left-hand sides respectively - had failed to get even the basics right: namely how to defend a pair of Jerome Boateng long balls that led to Bayern's first and third goals of the game.

"Situations like that are doubly tough to accept because the defenders should deal with them," Tuchel continued. "We've got to accept that we were not good enough. Bayern deserved to win. We have to dust ourselves down and start afresh - we need to."

Mainz on the horizon

Despite the setback, Dortmund remain Bayern's closest pursuers in second, albeit seven points off the top after failing to win any of their last three league outings. It is now hoped the international break will provide the five-time Bundesliga champions with some brief but invaluable time to regroup before taking on Tuchel's old flame 1. FSV Mainz 05 on Matchday 9.

"We've slipped up of late," bemoaned Dortmund captain Mats Hummels. "We have to show that we can go on a good run again. We made a great start by winning our first 11 competitive games of the season and after going four on the spin without a win, the objective for the game in Mainz has to be to get back on track."