Goals from Mladen Petric (pictured), Eljero Elia and Ze Roberto were enough for unbeaten Hamburg to see off Stuttgart and keep them ahead of Bayer Leverkusen on goal difference.
Leverkusen had put the leaders under pressure by repulsing a spirited comeback by champions VfL Wolfsburg to win 3-2 away.
That result kept them in second spot - five ahead of Bayern after they got their first away win of the season and moved up to fourth with goals from Mario Gomez, Bastian Schweinsteiger and Franck Ribery, plus two from youngster Thomas Mueller.
Hamburg grabbed the lead against the run of play when Petric beat Stuttgart keeper Jens Lehmann with a fierce drive from about 20 metres.
Hamburg, missing Paolo Guerrero and Collin Benjamin with ligament injuries, added another through Elia's long-range effort in the 58th minute.
Stuttgart pulled one back through Pavel Pogrebnyak four minutes later before Ze Roberto secured victory for Hamburg with a goal in added time.
"This club is alive," said Hamburg coach Bruno Labbadia. "It may be just the picture of this very moment but it is wonderful to see us top of the table. We showed a lot of patience today."
BAYERN IMPROVEMENT
Bayern fell a goal behind after only 10 minutes through Mats Hummels, their former player, and were disappointing for much of the first half hour.
Gomez's equaliser on 36 minutes breathed hope into the team and Ribery's entry in the second half added the necessary pace.
The Frenchman immediately wreaked havoc, helping set up Schweinsteiger for the second goal in the 50th minute before adding a third himself with a curling free-kick.
Mueller, a day before his 20th birthday, struck twice late in the second half to complete the rout.
Leverkusen captain Simon Rolfes scored twice and Stefan Kiessling added another to open a 3-0 lead over Wolfsburg before the home side, who had keeper Diego Benaglio sent off in the first half, battled back through Zvjezdan Misimovic and a Grafite penalty.
Leverkusen also finished with 10 men after the sending-off of Eren Derdiyok and survived the final 10 minutes of intense Wolfsburg pressure to get full points, leaving the champions to mull over their third straight defeat.
Hoffenheim also moved up to eight points with 3-0 win over Bochum.
