Bayern Munich missed the chance to go eight points clear at the top of the Bundesliga as they lost 2-1 at Eintracht Frankfurt.
Daichi Kamada and Amin Younes gave the hosts a two-goal lead at the break.
Robert Lewandowski tapped in his 26th league goal this term from Leroy Sane's cross to renew hope, but Hansi Flick's side were unable to find an equaliser.
Julian Nagelsmann's RB Leipzig can cut the lead to two points if they win Sunday's game in hand at Hertha Berlin.
The result marks another memorable victory for Eintracht over the 30-time German champions, with last term's 5-1 victory in Frankfurt being the prelude to the departure of Niko Kovac as Bayern boss and Flick taking over.
The result also extends their run to nine wins in their last 10 league matches as they stay fourth in the table.
While Flick led Bayern to victory in the Fifa Club World Cup, his side have underwhelmed since returning to domestic duties and repeated the lax start that contributed to their 3-3 draw against struggling Arminia.
Despite Lewandowksi edging closer to Gerd Muller's 49-year-old record of 40 top-flight goals in Germany, this time Bayern were made to pay for their flat opening.