Substitute Robert Lewandowski (right) celebrates with Arturo Vidal after scoring Bayern Munich's late winner against Hoffenheim.
The German champion had gone behind after nine seconds, as Kevin Volland (left) pounced on a defensive mistake to equal the Bundesliga's fastest goal with his team's first touch of the ball.
Thomas Muller leveled just before halftime, forcing in the loose ball with his thigh after a cross by Douglas Costa was only parried by Hoffenheim goalkeeper Oliver Baumann.
With 17 minutes to play, Bayern was reduced to 10 men when Germany defender Jerome Boateng was sent off for a second successive handball offense -- the latter when he tried to block a free-kick.
However, Eugen Polanski fired the resulting penalty against the post.