Bayern fell behind to a Jiri Stajner strike but responded with three goals in 14 minutes to set up an emphatic win and offer coach Jurgen Klinsmann some respite after a mid-week Cup exit at the hands of Bayer Leverkusen.
"We wanted this result," Klinsmann told Premiere television. "We knew we had to put everything into this match and I am delighted that the players did exactly that. It is going to be a tight race to the finish."
"This was a test of character today," Hertha manager Dieter Hoeness said, playing down their hopes of a first German title since 1931. "We just need to remain focused and disciplined."
They were briefly shocked when Hanover went ahead after 15 minutes with Stajner's curling shot but were level five minutes later through Daniel van Buyten, who rose above two defenders to head home a Bastian Schweinsteiger free kick.
Hamit Altintop added a third nine minutes later, with Hanover's defence by now in disarray, when he chased down a Klose header on the right, shrugged off a defender and slotted home.
