Brendan Rodgers’s Celtic were dumped out of the Champions League by AEK Athens as they slumped to a 2-1 loss in their third qualifying round, second leg in Greece on Tuesday.
The Scottish champions had been held to a 1-1 draw despite their opponents playing much of the game with only 10 men in last week’s first leg at Parkhead, and failed to turn the tie around after Rodrigo Galo gave the hosts a sixth-minute lead.
Croatian forward Marko Livaja’s strike early in the second half left Celtic needing two unanswered goals to progress.
Former Manchester City winger Scott Sinclair headed home with 12 minutes remaining to give Celtic hope, but AEK held on.
The Greek champions go on to face Hungarians MOL Vidi in the playoff round, while 1967 European Cup winners Celtic slip into the same stage of the Europa League after failing in their bid to reach the Champions League proper for a third straight season.
“I thought a lot of our build-up play was worth something from the game but you can’t defend that softly,” Celtic manager Rodgers told BT Sport.
“I still felt this was a game in which we had more than enough to win but you have to defend better than we did. We gave AEK a lot of problems but you have to defend properly and we didn’t do that.”
It is the first time that former Liverpool manager Rodgers has lost back-to-back games since taking charge of Celtic in 2016, after their shock 1-0 Scottish Premiership defeat at Hearts last Saturday.
Celtic will next face either Latvians Spartaks Jurmala or Lithuanian outfit Suduva for a place in the Europa League group stage.
“I don’t want to make excuses,” added Rodgers. “I’ve always said we needed to strengthen (in the transfer window) and hopefully we can do that now. It’s important that we have European football this year.”
Elsewhere, two-time European champions Benfica sealed a 2-1 aggregate victory over Fenerbahce.
Following a 1-0 first-leg home win, 19-year-old midfielder Gedson Fernandes netted a crucial away goal as they progressed despite Alper Potuk equalising on the night for Fenerbahce.