Ange Postecoglou says Celtic had to eliminate the fear to survive a siege and reach the Europa League group stage.
The Aussie was hugely satisfied to secure a spot in tomorrow's draw after a tension-packed night in Alkmaar.
Celtic were 3-0 up on aggregate and cruising through after Kyogo Furuhashi opened the scoring, but two catastrophic blunders before half-time from Joe Hart and Carl Starfelt put progression in the balance.
Postecoglou admitted his team lost their way and got scared for a spell before a resilient final hour saw the job through.
It wasn’t all good news with new hero Furuhashi sustaining a knock meaning he’ll need assessed before Sunday’s crunch Premiership clash with Rangers along with shoulder-injury victim Greg Taylor.
But the ability to see off the temporary terrors heartened Postecoglou who said: “Our evolution as a team will depend on how we overcome the challenges we face.
“The challenge was how we would respond to the individual mistakes.
“We didn’t react well initially. In the last 30 minutes of the first half we second-guessed ourselves, got apprehensive and worried about making another mistake.
“The last half hour of the first half we were under siege without any real composure or plan to play through it.
“We just lost belief. We had to break through that barrier.
“I told the players that fear is the biggest impediment to progress and we had to eliminate that from our game.
“Mistakes will happen. We just have to respond better to them and believe in our football.”
Postecoglou refused to hammer Hart and Starfelt and continued: “They are two human beings, they are going to make mistakes.
“We started the game well, we scored, but the two goals set us back. Second half we dug in when we had to.
“Joe was obviously disappointed, but he made a couple of outstanding saves and Carl defended really strongly in the second half.
“Mistakes are a part of football, it’s the reaction to them that’s important.
“It was a different type of performance. We had to dig in. It’s great we showed that resilience.”
Postecoglou can add Josip Juranovic to his backline for Ibrox and Shamrock Rovers defender Liam Scales is also wanted.
But the boss said: “I’ve already said we’re not the finished product. We can’t be at this stage. You need to keep things in perspective.
“It’s been an extraordinary four weeks when you think about what we’ve done in that period of time.”
On Taylor and Furuhashi for Ibrox, he said: “Greg’s got a shoulder problem but as yet we don’t know the extent of it. I thought Adam Montgomery was outstanding coming on.
“Kyogo got a bit of a knock, so it’s going to be about recovery now over the next 24, 48 hours. Then we’ll assess how everyone is.”
Beforehand, the draw excites and he said: “It means we’re going to be playing in one of the elite competitions against good quality opponents and ensuring there will be some more special European nights in this season.”
