Lennon: 'We shot ourselves in the foot' in shock Cluj defeat
The Celtic manager said his side "gave it away" as they were dumped out of the Champions League.
Neil Lennon admitted he was mystified by Celtic's mistakes as they crashed out of Champions League qualifying with a 4-3 home defeat to CFR Cluj.
After drawing 1-1 in Romania last week, Celtic were 1-0 down in less that half an hour in Glasgow but dragged themselves back to a winning position, only to let it slip with two late goals that knocked them out of the competition.
Though James Forrest, Odsonne Edouard and Rryan Christie all found the net, Celtic's defending let them down and Lennon said they started the match poorly.
"The first half we were so passive, no tempo, I don't know where that came from," he said. "We weren't physical or aggressive enough and certainly didn't work hard enough to stop crosses, second balls. All the nuts and bolts of the game.
"We got a warning beforehand and we didn't stop the cross and then we do the exact same thing again.
"At half-time we got after them a little bit and got the right response but we shot ourselves in the foot with the goals we conceded. We had the lead twice and we have given it away."
Lennon revealed that he had frank words with his players at half-time and was pleased with the initial response before they were stunned by Cluj's fightback.
"I said to them 'You're blowing it, you're playing as if it's a friendly. I don't know if you're disrespecting the opponent but you're flat. This is a Champions League qualifier and at this minute we're going out of the competition. Is that what you want?'
"And then of course we come out and score and you think we'll kick on and then settle. The second goal gives them a bit of impetus again."
Defeat puts Celtic into the Europa League play-offs where they will face Sherrif Tiraspol or AIK. Lennon admitted he would have to lift the players and take some flak but minds would have to focus on the task ahead.
"We've only ourselves to blame," he said. "It's hugely disappointing for us all.
"We're going to have to accept the criticism that comes our way. We need to regroup and make sure we qualify for the Europa League."