"Catastrophic" to me means the end. This is far from being the end.Ange Postecoglou, Celtic manager, says he hasn't done a "good enough job convincing" the club hierarchy that they need more squad reinforcements after their Champions League exit.Midtjylland beat the Scottish team 3-2 in aggregate in the second qualifying round. They lost the second leg 2-1 in extra time in Denmark.Postecoglou stated that it was bad to be inexperienced.After his second game, he stated that he still believed it was his responsibility."I'm the one who's in charge, and if we don't have players then obviously I haven’t done a sufficient job convincing people that we need them."I don’t say it because I’m a martyr. I think that’s my responsibility."Celtic's starting XI in Demark for the second leg was only 23 years old, with Dane Murray (18) and Stephen Welsh (21), at centre-back.Midtjylland responded to Celtic's defense flaws twice, even though they took the lead in tie with captain Callum McGregor's brilliantvolley.Due to quarantine rules, the club was unable to sign new signings Kyogo Furuhashi and Carl Starfelt. Postecoglou stated that the current group needs more support.The Australian said that she had been trying to be as assertive as possible about what they needed to do and that the difficulties faced were well documented."It's possible that I was not clear enough. I don't know. That's something I believe I have been consistent with. More players are needed. We are working hard to get these players in."Our supporters want us to bring in the reinforcements we need, and I just have to continue reinforcing how strongly I can."Reaction: "It's going take two years to get it back"BBC Radio Scotland: James McFadden, former Scotland forwardFor Celtic, it's a heart-breaking experience. They have made poor decisions in big moments. It could be a much bigger rebuild than many people believe. The team was not strengthened by any player Celtic brought in the last year.Postecoglou stated that he had been asking for players as well as reinforcements. He's not getting them.Premier Sports: John Hartson, former Celtic strikerCeltic are going through a huge transition. They have lost many key players and the captain. It will take at least two years to get it back on track.It all depends on what they give Ange. What amount will Celtic give him? He won't get two years.Chris Sutton, former Celtic striker on Premier SportsCeltic will struggle to make it into the Europa League. It is a process of building.Ange should ask Dominic McKay, Chief Executive, to apologize for the mess he left. This is an awful manager. He must make a complete turnaround in the next year.For a long time, there have been problems that need to be addressed. Dane Murray, an 18-year-old defensive player, was sent to the deep end. It is embarrassing and poor management. This is the norm.