Nurnberg spoiled Ottmar Hitzfeld's return as Bayern Munich manager with a 3-0 win at the Franken Stadion.
Hitzfeld returned to Bayern on Wednesday after Felix Magath's sacking, but his second spell in charge got off to the worst possible start at Nurnberg.
Ivan Saenko set Nurnberg on their way with the opening goal after just 13 minutes.
Markus Schroth added a second on 71 minutes and Robert Vittek sealed a comfortable win for Nurnberg with his side's third four minutes from time.
The result means Bayern have taken just one point from their first three matches after the winter break.
The reigning champions remain eight points behind the leaders and they face a major battle to keep hold of their title.
Click on fixture for full match summary
Nurnberg 3-0 Bayern Munich