Heading into the last round of matches, Gladbach are surprise leaders in Group B, a point ahead of both Shakhtar Donetsk and Real, who are third.
Real must beat the Germans in Madrid to guarantee a last 16 berth after home and away defeats to Donetsk in the group stages.
A home defeat would see Real lose their remarkable record as the only team to have always progressed from the group stages of the Champions League.
“We have the best starting position of all the teams in the group and we have earned it thanks to our efforts,” Gladbach midfielder Christoph Kramer said Tuesday before flying to Spain.
Gladbach will qualify as group winners with a victory, but will also go through with a draw or even a defeat if Inter Milan and Shakhtar draw in Wednesday’s other Group B game.
The Germans are chasing a first appearance in the knock-out stages since reaching the semi-finals of the old European Cup in 1977/78.
“We have a ‘final’ in front of us,” said coach Marco Rose.
“We’re all looking forward to it, but we know how difficult the task will be.
“We will have to defend with zeal and passion, but with our qualities, we will have opportunities to score.”
Gladbach’s attack will be spearheaded by their French duo of Marcus Thuram and Alassane Plea
Thuram scored twice in the 2-2 home draw against Real, while Plea has scored five Champions League goals, including a hat-trick in the 6-0 demolition of Donetsk.
Gladbach are without defender Tony Jantschke, who has a hip injury, midfielder Ramy Bensebaini, quarantining with the coronavirus, and attacking midfielder Jonas Hofmann, out with a leg injury.
