Arturo Vidal's fourth goal in as many league games shot Bayern Munich to a 1-0 win at Eintracht Frankfurt and an eight-point lead at the top of the Bundesliga on Saturday.
Bayern's win means that they cannot be caught before the winter break, which starts on December 17, and makes them 'Herbstmeister' (Autumn champions) for the seventh season in a row.
Bayern head coach Jupp Heynckes rang the changes from Tuesday's 3-1 win at home to Paris Saint-Germain in the Champions League, starting midweek goalscorers Robert Lewandowski and Corentin Tolisso on the bench.
The biggest shock however was that third-choice goalkeeper Tom Starke, who had been working in Bayern's academy after retiring last season.
The 36-year-old was thrown into the fray after Sven Ulreich, who has played in place of Manuel Neuer since the Germany captain fractured his foot in September, injured his groin in the warm-up.
"I have been doing this for a few years and the juices are still flowing," said Starke, who came out of retirement in September and was named in the club's Champions League squad.
Frankfurt made a bright start, but Bayern grabbed what proved to be the winner on 20 minutes.
Joshua Kimmich swung in a cross which found Vidal unmarked at the back post to score to decisive goal.
Having already picked up a first-half yellow card, Vidal narrowly escaped a red card after fouling Marius Wolf with just under 40 minutes left and Heynkes hauled him off soon after.
Bayern extended their lead at the top of the Bundesliga after RB Leipzig conceded a late equaliser in their 2-2 draw at home to Mainz, whose replacement striker Emil Berggreen equalised three minutes from time.
The hosts took the lead at Leipzig's Red Bull Arena when midfielder Kevin Kampl fired home on 29 minutes, but Mainz equalised ten minutes later when Robin Quaison slotted home a rebound from a parried free-kick.
Germany striker Timo Werner restored Leipzig's lead in the third minute of first-half stoppage time with a controversial penalty.
The decision was backed up by the VAR after Diego Demme went down in the area, but replays showed there was only the faintest of touches from Mainz defender Leon Balogun.
The incident lingered and Mainz's disgruntled coach Sandro Schwarz was sent to the stands for the final 15 minutes before Berggreen's late header.
Third-placed Schalke later missed the chance to go second when they drew 1-1 at Borussia Moenchengladbach, who are fourth, as Thorgan Hazard cancelled out Christoph Kramer's first-half strike for the hosts at Borussia Park.
Former league leaders Dortmund dropped out of the top six for the first time this season after crashing 2-1 at home to strugglers Werder Bremen.
Dortmund are without a win in their last eight league games and the defeat could well be the last for head coach Peter Bosz.
"The first half was really bad and I am the one responsible for it. The disappointment is very deep," said the glum-faced Dutchman.
Bremen went ahead when Germany Under-21 midfielder Maximilian Eggestein fired home unmarked at the edge of the area on 26 minutes.
Pierre-Emerick Aubameyang brought the hosts back on level terms when he bundled home Shinji Kagawa's 57th-minute cross, which appeared to hit the arm of defender Philipp Bargfrede.
But Bremen restored their lead eight minutes later when a header from Czech defender Theodor Gebre Selassie hit the boot of Dortmund goalkeeper Roman Burki on its way into the net.
Kagawa wasted a to equalise for Dortmund with 15 minutes left when he fired over with the goal at his mercy after Aubameyang had slipped over.
Hamburg stay three points clear of the relegation places after their goalless draw at home to mid-table Wolfsburg.
Borussia Dortmund 1
(Aubameyang 57) Werder Bremen 2
(Eggestein 26, Gebre Selassie 65)
RB Leipzig 2
(Kampl 29, Werner 45+3-pen) Mainz 2
(Quaison 39, Berggreen 87)
Eintracht Frankfurt 0 Bayern Munich 1
Hamburg 0 Wolfsburg 0
Borussia Moenchengladbach 1
(Kramer 23) Schalke 04 1