Borussia Mönchengladbach has once again proven itself to be a Bayern specialist and has at least given the entire Bundesliga some hope.
The guests around the goalkeeper Yann Sommer, who had been holding gigantic for a long time, won a 1-1 (1-0) in the top game of the Bundesliga on Saturday evening.
After a blackout by Bayern defender Dayot Upamecano, Marcus Thuram (43rd minute) scored Gladbach's surprising lead at the break.
The Munich Tor-und-Sieg-Express, which was so overwhelming at the start of the season, needed up to the 83rd minute this time before the strong Leroy Sané hit the target with a well-placed left-footed shot from Jamal Musiala.
With ten points, Bayern maintained their lead in front of Union Berlin, who are tied.
Gladbach has eight points.
75,000 spectators in the sold-out arena couldn't believe their eyes for a long time.
Bayern seemed to beat themselves – in the back with a capital blackout by Upamecano when conceding a goal.
And up front, the 15-goal machine faltered in the first three matchdays, the ball just couldn't find its way into the goal - until Sané struck.
Fear opponent is a fear opponent
A highlight was the 61st minute, when star striker Sadio Mané failed twice free-standing in the seemingly invincible summer.
Before the break, the Senegalese were denied two offside goals by video evidence (34th/39th minute).
It was almost surreal how Daniel Farke's hard-fighting Gladbachers initially withstood Bayern's assault.
Before the game, there was a lot of talk about whether the Gladbachers were a "fear of opponents" for Bayern because of their good recent record against the record champions, including last year's 5-0 cup gala.
"The answer will be there on Saturday evening," Bayern coach Julian Nagelsmann said on Friday, adding: "Our players are not afraid of any opponent, not even Gladbach."
That's how they played - but then defensive giant Upamecano made a serious mistake.
The 23-year-old Frenchman, whom Nagelsmann preferred in defense to newcomer Matthijs de Ligt, had one of those dropouts that had cast doubts on him last season.
After a throw-in, Gladbach's Christoph Kramer hit the ball up and forward from his own half.
Upamecano wanted to clear it easily, missed the ball - and Thuram irresistibly stormed towards the Bayern goal.
The Frenchman also overcame the helpless national goalkeeper Manuel Neuer.
"Catastrophic mistake," judged record national player Lothar Matthäus as a Sky expert.
The scene turned the game upside down and meant Bayern's first deficit of the season.
They should have been in the lead long ago.
There was a kind of permanent siege of the Gladbach half.
But Sommer made a splendid save from the first action with a header from Mané.
After the break, the Bavarians stormed towards their fans, who first celebrated with a choreography well worth seeing and later with lots of smoking pyrotechnics for "50 Years of the South Curve".
There was chance after chance and shot after shot - and umpteen summer parades.
Nagelsmann drew all the jokers, brought Serge Gnabry and Musiala, who was still slightly injured, and promptly prepared the Sané goal.