De Boer's team take on Celtic tonight in a group that also sees AC Milan entertain Barcelona, and the Dutchman feels that his side can only realistically challenge for a runners-up spot in Group H.
"We are playing for second place," De Boer told reporters. "It's obviously always nice to win, to lose is the worse option, but a draw could be enough because then we play Celtic at the Amsterdam ArenA.
"If we win, it could be very difficult for Celtic to get close to second place and if we lose, Celtic takes a great advantage.
"The players have to enjoy this kind of atmosphere. When you're young, you want to play in stadiums like this, in that kind of atmosphere."