Borussia Moenchengladbach's push for a Champions League place was stalled by Freiburg who clinched a 1-0 win in the Bundesliga on Friday.
Gladbach, enjoying their best season since 1984, remain in fourth place - the final Champions League qualifying spot - on 56 points.
However, Bayer Leverkusen could replace them on Saturday should they defeat defending champions and league leaders Bayern Munich.
With just four games left, Freiburg boosted their Europa League hopes with victory secured by Nils Petersen's goal in the 58th minute.
Petersen had only been on the pitch for a minute after replacing Roland Sallai when he powerfully headed home from a free-kick.
To make matters worse for Gladbach, their French striker Alassane Plea was red-carded in the second half.
French striker Marcus Thuram, who made global headlines last weekend when he took a knee to protest the death of George Floyd, was unable to breakthrough despite his side having the best of the first hour.
When Plea was sent-off, Gladbach's sporting director Max Eberl protested too vigorously through his anti-coronavirus face mask and was also dismissed.
Plea will now miss next weekend's home clash with Bayern Munich.