Having been paired with the champions of Spain, England and Germany in Real Madrid, Manchester City and Borussia Dortmund, De Boer has tempered his expectations to the extent that finishing third - and securing a place in Europe's second tier competition - would satisfy the former Holland defender.
The Amsterdammers go into Wednesday night's clash with Dortmund three points behind second-placed Madrid with two games remaining, but with two more than rock-bottom City.
"We're going all out to win," said De Boer at his pre-match press conference, "because we would like to remain in the Champions League. It is difficult but we are still going for it."
He added: "If we are honest, though, it would be great if we can finish third and get into the Europa League qualification places.
"That would certainly represent a nice (Champions League) tournament. Look at our opponents."
For Dortmund, the equation is simple; a point in Amsterdam and they qualify. Sporting director Michael Zorc is satisfied with their progress but will not get carried away until their progress is assured.
"Our position is solid, but we are still missing a point," he said in Ruhr Nachrichten. "We realise that we need a great performance once more, as we have already shown in this Champions League."
Dortmund's recent record in the tournament has been poor - they have not reached the last 16 since 2002-03 - and Zorc admits their results this season have surpassed expectations.
He added: "Of course we could not expect to get four points against Real Madrid and win the head to head comparison. But we know that our team has enough quality to play at this level."
Dortmund should have captain Sebastian Kehl available as he has passed a fitness test after missing the last two Bundesliga games with a knee injury.
Ilkay Gundogan should also be available to take his place in midfield after being replaced against Greuther Furth at the weekend due to a back complaint.