After losing 4-1 in the first leg of their third-qualifying-round match to Legia Warsaw, the Scottish champions were beaten 2-0 at Murrayfield to slip into the Europa League
The Bhoys were 4-1 down after the first leg and lost 2-0 at Murrayfield on Wednesday evening to ensure that they drop down into the Europa League qualifiers.
The heavy defeat gives coach Ronny Deila a horrendous start to life as boss of the Scottish champions and the club is now poised to lose some of its star players, such as goalkeeper Fraser Forster and defender Virgil van Dijk.
Celtic had earned plaudits and prize money from ventures into – and, once, past – the group stage of the Champions League under Neil Lennon, who left his post at the end of last season but Deila will now have to focus on lower targets.
Michal Zyro put the first goal past a limp home side with 10 minutes left of the first half, picking up on a long ball and holding off his marker to fire past Forster.
Michal Kucharczyk had the last word just after the hour, going around the keeper to score, but Celtic's hopes had long since been extinguished.