Bayern have been irresistible in their last two games, scoring seven in each, and suddenly appear to have gained momentum at the right time in the season after a slump which including defeats to Borussia Monchengladbach and Bayer Leverkusen.
If anyone can stop find a way of stopping them, however, it is the 73-year-old Rehhagel, who led Kaiserslautern to an improbable Bundesliga title in 1998, the only time a promoted team has won the championship, and won Euro 2004 with Greece, an equally unlikely achievement.
Rehhagel's total of 18 wins over Bayern at various stages during his career is more than any other coach has managed and "King Otto" is always happy to put one over on the Bavarian club who sacked him after less than a season back in 1996.
"We create plenty of chances but we can't put the ball in the net," said Rehhagel, who has managed one win and two defeats since becoming Hertha's third coach of the season.
Jurgen Klopp's team host sixth-placed Werder Bremen and are attempting to set a club record of 20 Bundesliga matches without defeat, their last reverse having come against Hannover 96 in September.
"Maybe Leverkusen's attacking goal will favour us," said striker Marco Reus, whose side won the corresponding fixture last season 6-3.
"We simply have to work harder in training and we will start winning again."
Hoffenheim, Bayern's victims last Saturday when they lost 7-1, hope for an easier time when they host VfB Stuttgart on Friday evening.
"Maybe we're not the only village idiots, it's happened to someone else" he said. "That was a confirmation of how strong Bayern are."
