NEIL LENNON has spoken candidly after watching his side crash out of the Champions leave as the Celtic manager brands it "bitterly disappointing".
Defensive errors contributed as Celtic suffered a 4-3 defeat, going out of the Champions League 5-4 on aggregate.
Portuguese champions Porto threw away their one-goal lead to Krasnodar and conceded three goals at the Estádio do Dragão, eventually being knocked out by the Russian club on away goals. You've got to do the basics well - you've got to stop crosses, close people down, get your head on things - and it was nearly as if we scored and wanted to switch off.
Celtic drop into the Europa League where they will face either AIK Stockholm of Sweden or Moldovan side Sheriff Tiraspol in the play-off round.
James Forrest and Odsonne Edouard were able to hit back and put Celtic back in the driving seat, but Billel Omrani scored either side of Ryan Christie's effort to give Cluj the advantage, while substitute George Țucudean rounded off the scoring in added time to dump the Scottish champions out of the Champions League.
"We need a miracle to qualify". The Hoops will be the favourites to advance to the next round considering that they managed to score a vital away goal, as well as not lose during the last leg.
"The first goal, we got a warning before that, and we still didn't stop the cross and the guy's got across for a run".
Whether Mikey Johnston plays in the game is uncertain as he is set to undergo a late fitness test. If you don't do the basics defensively well enough then at this level you get punished.
"We had the lead and we've let it slip through our own decision making", Lennon told BBC Scotland.
Celtic have also been playing positive football in the Scottish Premiership so far, having won both of their league games by big margins and will be looking to continue this trend against Cluj.