Douglas Costa's long-range strike gave Bayern Munich a 1-0 victory at bottom side Darmstadt on Sunday to reinstate his side as Bundesliga leaders ahead of its showdown with RB Leipzig.
Bayern hosts second-placed Leipzig at the Allianz Arena on Wednesday in a mouth-watering clash with both teams on 36 points, but the Bavarians are top on goal difference.
Costa's ferocious dipping shot from 30 metres out on 71 minutes was the bright highlight of a lacklustre Bayern display as Darmstadt battled its illustrious opponents, running seven kilometres more as a team.
Carlo Ancelotti's Bayern had been temporarily usurped from top spot in Germany for 24 hours by Leipzig's impressive 2-0 win at home to Hertha Berlin on Saturday.
However, this was a below-par display from Bayern, especially in the first half, against a limited Darmstadt team who suffered its seventh straight league defeat.
With Jerome Boateng already out after needing a shoulder operation, Bayern's captain Philipp Lahm withdrew just before kick-off after pulling a thigh muscle in the warm-up and was replaced at right-back by Rafinha.
With an eye on Leipzig, Ancelotti rotated with both Germany midfielder Joshua Kimmich and Franck Ribery started on the bench.
The Italian coach had demanded a performance with "maximum intensity", but Bayern did exactly the opposite, failing to create a clear chance in the opening 25 minutes at the Boellenfalltor stadium.
Without Arjen Robben or Ribery on the flanks, Bayern lacked a creative spark and Costa made little inrode into the Darmstadt defence, until his thunderbolt of a shot settled the result.
Bayern's hot-shot striker Robert Lewandowski was harassed Darmstadt defenders whenever he got the ball.
Ancelotti resorted to his prefered 4-3-3 formation, even though some of Munich's biggest wins this season have been achieved with a 4-2-3-1 line-up.
Darmstadt's caretaker coach Ramon Berndroth 'idolised Ancelotti as a youngster', but his side showed Bayern little respect, created a few half chances and never allowed Munich's stars time on the ball.
Ribery came on for the lacklustre Arturo Vidal for the final 20 minutes just before Costa's superb winner.
Thomas Mueller pulled defenders away from the middle and with a clear view of goal, Costa unleashed a fierce shot from 30 metres out which dipped inside the top left-hand corner.
Darmstadt's best chance came when midfielder Peter Niemeyer headed straight at Bayern's goalkeeper Manuel Neuer from a free-kick on 77 minutes.