The German champions, thoroughly dominant in the second half, may feel particularly hard done by not to have taken at least a point at the Westfalenstadion.
While chances were missed by both teams, it was Pierre-Emerick Aubameyang’s 12th of the season which secured the points for Borussia.
Tuchel’s 3-3-1-3 - changing eventually to 3-4-3 and latterly a 5-3-2 - was effective in extending the pitch as much as possible, and giving the team greater stability in defending counters.
On the inside, Dortmund’s coordinated movements and flexible structures in the first half inspired their first home win over Bayern since April 2012.
Mario Götze and Andre Schürrle, the two marquee summer signings, focused their efforts on Thiago and Philipp Lahm without the ball. In defence, the right-sided Matthias Ginter shadowed Robert Lewandowski to great effect, while Marc Bartra showed impressive discipline after collecting an early yellow card.
His first win over Bayern at the fifth attempt as Dortmund coach, the victory represents a triumph of huge proportions for Tuchel. Narrow defeats to Bayern, like the German Cup final, had become normal for the yellow-and-blacks. But this result pins Bayern back to just three points, but it proves to validate his efforts to rebuild this Dortmund side into something more substantial.
Carlo Ancelotti’s tenure at Bayern Munich is taking a while to move into second gear. A comedown from the exit of Pep Guardiola was naturally expected, but the instability at the Allianz is a cause for concern.
In a normal season, the champions would have already done enough to be clear of their rivals, but the arrival of RB Leipzig has upped the stakes.
After recent struggles against Hoffenheim and Dortmund, Ancelotti’s men welcome Leverkusen next week, who will cap off a demanding November - there’s still the small matter of Leipzig to come in December.
Managing the oldest squad in the Bundesliga, Ancelotti has to find a better mix immediately between the likes of Lahm and the young stars, like Joshua Kimmich and Kingsley Coman.
Bayern’s second half performance was a sign of encouragement, a minor positive to take from defeat. When Dortmund’s intensity dropped, Thiago and Franck Ribery bravely looked to assert their quality on the game.
But aside from Ribery’s offside goal, chances were limited. With Bayern playing catch-up, the questions from outside the Bayern camp are becoming ever louder.
Taking on his former club for the first time since his 20 million euro return to Dortmund, Götze certainly had something to prove. As he testified in a recent interview, the attacking-midfielder is going through an evolution of his game, shifting from a high-impact player to one who can provide stability, control and intelligence to a team.
Indeed, it was those qualities that Götze eschewed in Dortmund’s victory. In the half-space positions, the German international was pivotal, in possession and against the ball. It was, first, his sweeping, diagonal run from deep that created the opening for the goal, before he clipped the ball into a tantalising area for Aubameyang to score.
Against the ball, Götze was excellent, an indication of the extra work he has put in to get up to speed this season. He pressed with intensity and aggression towards the spaces around Thiago, who dropped into the defensive line to gain possession. Although he tired and was substituted, Götze was Dortmund’s most important player, which will go along way to endearing himself to the locals.
Among a number of issues, Bayern’s passiveness is a notable weakness compared with Guardiola’s teams. In attack, there’s a serious over-reliance on Robert Lewandowski, who was statistically the best attacker in the Bundesliga before Saturday.
His 11 goals were backed up by the highest number of clear scoring situations - either for him or created by him - in the division. The Pole inspired five of the last six goals (goals and assists) for Bayern in all competitions.
The varying patterns of play have dissipated in the handover of power. There’s no intent to create numerical or qualitative overloads in the wide positions, nor to create a free man in midfield - Bayern’s second highest scorer is jack-of-all-trades Kimmich with four goals, coming in a short span of the season.
Thomas Müller hasn’t scored in the league and looks lost in a wide-right position. Arjen Robben and Franck Ribery aren’t durable enough to avoid injury for a couple of weeks at a time. Behind Lewandowski, there’s no genuine competition for the main striker berth. If Bayern are going to maintain a competitive fight this season for titles, Ancelotti needs goals from somewhere else.
Few could have predicted such a thrilling, open-ended start to the season. RB Leipzig are the first newly-promoted team in league history to avoid defeat after 11 matches and hold a three point lead over Bayern Munich. The German champions themselves are three ahead of Borussia Dortmund, while Hoffenheim could move third tomorrow with a win over Hamburg.
Even before the first-third of the season is passed, the dynamics of the league are interesting. Leipzig, though pragmatic management and smart squad building, have been no fluke so far and will run Ancelotti’s men close this season. With Dortmund now close by, it would be foolish to dismiss anything other than a multi-team championship race.