The Hoops crashed-out of the qualifiers after a heavy aggregate defeat to Legia Warsaw.
After a 4-1 first-leg defeat, Ronny Deila's side needed to produce an historic fight-back last night at Murrayfield to have any chance of progressing to the next qualifying round. Instead, the Polish champions scored a goal in either half to seal an emphatic 6-1 victory over both legs.
The defeat means that Celtic will now drop into the Europa League play-offs.
Manager Ronny Deila described it as a "black day" for Celtic, and admits it may affect their ability to attract top players to the club.