Dusseldorf, who have not been in the top tier for 15 years, will travel to the capital for the first leg on Thursday before hosting Hertha five days later, with the winner playing in the Bundesliga and the loser in the second division next season.
It is the fourth year of the Bundesliga relegation play-off, with the second-division side gaining promotion only once, in 2009.
And Dusseldorf forward Sascha Rosler says Hertha will be expected to continue that trend.
"They are going to be two very difficult games," he said on Bundesliga.de.
"Hertha are clear favourites, but they have had problems this season, otherwise they would not have played such a bad season, and we have got to take advantage of that.
"We need to get into a good position in Berlin and then, with the fans behind us in the second leg, finish it off.
"We have got to give it all we have got. We were under so much pressure recently to finish third and now we can shake that off and play freely."
Hertha coach Otto Rehhagel was a spectator at the Dusseldorf Arena on Sunday as the home side clinched third with a 2-2 draw against Duisburg, and he was given plenty to think about.
"It has got to be clear to us that these games will not be easy," he said.
"We have got to throw everything into the mixer once again."