A seven-point haul from their last four matches has seen Hamburg move up to ninth in the Bundesliga standings on 17 points, the same amount as Hannover in sixth.
A win on Friday would therefore see Hamburg leap-frog the three teams immediately above them ahead of this weekend's fixtures, but Fink is also well aware of what a defeat would mean for his side.
"We said that we wanted to get seven points from our games against Freiburg, Mainz and Dusseldorf," he said.
"We are in a good condition and we are gaining self-confidence with every victory.
"A win could establish our place in the top half of the table and allow us to take advantage of the fact that our rivals are playing each other, but we must also keep an eye on what's going on below us.
"If we were to lose, then Dusseldorf would only be three points adrift, for example."
Nevertheless, Fink is taking a positive approach and is looking forward to visiting the Dusseldorf Arena for a night game.
"I used to love playing at night," he said at a press conference. "I'll be happy if that goes for our team too - it worked well in Augsburg (2-0 away win last month).
"Of course we want to win and that has got to be our aim, but it will also be very hard."
Third-bottom Fortuna are still searching for their first home victory since returning to the top flight after a 15-year absence, but their coach Norbert Meier believes they have been unlucky not to end that run before now.
"The league table is not how we would like it to be right now, but a win would improve that," he said.
"It's frustrating that we are not rewarding ourselves fully. We have got to into this game with motivation and determination."
Fortuna, who have drawn four of their six home games, have an injury doubt hanging over striker Robbie Kruse after he missed a few training sessions this week while Dani Schahin and Oliver Fink are both still out.
Dennis Aogo will take the place of the injured Marcel Jansen in the Hamburg defence.