Bayer Leverkusen beat Bayern Munich 2-0 with two late goals to deal the visitors a serious blow to their Bundesliga title hopes on Saturday.
Stefan Kiessling put the home side ahead in the 79th minute and Karim Bellarabi put the result beyond doubt in the last minute with his first ever goal for Leverkusen.
Leverkusen had failed to beat Bayern in the league in 14 previous attempts since a 4-1 victory on Aug. 24, 2004.
Bundesliga leader Borussia Dortmund was scheduled to host Mainz later Saturday, when the defending champion could open a seven-point gap in the standings with a seventh consecutive league win.
Elsewhere, Hertha Berlin ended its 12-game winless run with a 1-0 victory at home over Werder Bremen to climb out of the relegation zone.
Schalke lost 2-1 at Freiburg, Stuttgart romped to a 4-0 win at Hamburger SV, Kaiserslautern and Wolfsburg drew 0-0 and relegation-threatened Augsburg drew 2-2 at Hannover.
Despite leaving Franck Ribery on the bench after his heavy knock in France's 2-1 midweek win in Germany, Bayern dominated the first half and missed several chances to take the lead.
Leverkusen 'keeper Bernd Leno, who turns 20 on Sunday, produced a fingertip save to deny Arjen Robben in the 13th, and Bayern's frustration threatened to boil over after half an hour when Rafinha had to step in to separate Jerome Boateng and Mueller during a heated argument.
Leverkusen defender Manuel Friedrich cut out Mario Gomez's goalward shot after Leno was beaten. Leno pounced gratefully on the rebound.
Manuel Neuer produced a great reflex save to deny Kiessling in the 66th, but was helpless to prevent the former Germany international from scoring from close range when Eren Derdiyok flicked the ball on.
The visitors were caught on the break when Simon Rolfes set Gonzalo Castro free on the right. He crossed to the middle where Bellarabi timed his run perfectly to fire to the bottom left corner.
Leverkusen next hopes to overturn a 3-1 deficit to Barcelona in the Champions League on Wednesday.
Fourth-placed Schalke failed to close the gap on Bayern as Freiburg climbed off the bottom.
Schalke was missing topscorer Klaas Jan Huntelaar following the Netherlands striker's clash of heads with England defender Chris Smalling on Wednesday, and Peru winger Jefferson Farfan was dropped.
"He told me he was tired, that he was kaputt, so I don't need him for this game," Schalke coach Huub Stevens said.
Sebastian Freis scored his first goal for the home side in the 18th, and Daniel Caligiuri tucked away a penalty to make it 2-0 in the 66th.
Teemu Pukki pulled one back in the 72nd, seconds after going on as a substitute, when United States midfielder Jermaine Jones played the Finn through.
Lewis Holtby came agonizingly close to equalizing in the 84th when he hit the bar, then Schalke defender Kyriakos Papadopoulos earned a second yellow card with three minutes remaining.
Stuttgart deservedly took the lead in Hamburg in the 23rd when Vedad Ibisevic easily eluded Slobodan Rajkovic before shooting inside the left post.
It got worse for Rajkovic eight minutes later when the Serbian defender gave away a penalty for his challenge on Shinji Okazaki. Zdravko Kuzmanovic made no mistake from the spot.
Rajkovic was unfortunate to give away another penalty after the break, when Martin Harnik made the most of his outstretched arm. Kuzmanovic duly made it 3-0 in the 47th.
Hamburg's Jose Paulo Guerrero was sent off for a terrible challenge on Sven Ulreich in the 54th. Replays showed the Peru striker made no attempt to play the ball when he caught the Stuttgart goalkeeper studs up from behind.
Austria striker Harnik rounded out the scoring in the last minute.
Hannover's unbeaten home record looked under threat when Axel Bellinghausen drilled a 20-meter (yard) effort beyond Ron-Robert Zieler in the 12th.
But Karim Haggui equalized with a header from a corner in the 33rd, after Augsburg squandered a host of chances.
Mame Biram Diouf put Hannover in front in the 69th, but Jan-Ingwer Callsen-Bracker equalized for Augsburg from the penalty spot in the 89th.
Nikita Rukavytsya gave Hertha coach Otto Rehhagel a winning debut at home against the 73-year-old's former side, when his mis-hit bounced over the helpless Tim Wiese for Hertha's first goal in six games across all competitions.
Kaiserslautern replaces Freiburg at the bottom after its 14th consecutive game without a win.