But now Ronny Deila’s side have been given an extraordinary second chance and will line up against Maribor in the play-off round, with their sights set once again on the group stages.
Uefa decided today Legia had fielded an ineligible player, Bartosz Bereszynski, in the second leg at Murrayfield on Wednesday night, and Celtic have been given a reprieve.
It is unbelievable that this has happened twice to Celtic in the space of a couple of years after the FC Sion case in the Europa League in 2011. Someone is definitely looking down on them kindly.
It is a chance Celtic never thought they would get, especially after turning in such an abject performance at Murrayfield to lose 6-1 on aggregate.
Celtic will be delighted they have been given another shot at the Champions League, and are guaranteed European football until Christmas.
But that doesn’t take away the fact that they were poor over two legs against Legia and Ronny still has a lot of work to do to get the team playing a lot better than they did.
The players have to improve their level of performance and I think one or two acquisitions have to be made as well.
After what has happened I think Celtic have to push to get a couple of players in prior to the play-off round.
If they say they have targets they are thinking about getting, why not get them in now?
I don’t think it is necessarily about the transfer fee. I think Celtic have to consider breaking their wage structure.
I know it is difficult in Scotland but, for the sake of making it easier to get through these qualifiers, you have to get a better quality of player.
You have to invest at a level where you are able to attract better players. I think the board have to consider upping the ante for the basic wage.
To entice a player to get you into the Champions League, you have to increase the salary on offer.
I don’t want it to be a damaging amount, it has to be affordable, but they need something to appease the fans.
We are only talking about a couple of positions – striker and creative midfielder in particular – but that bit of quality can be the difference between making the Champions League or not.
There is now an opportunity that everyone thought was gone and Celtic have to make the most of it.
Everyone was expecting an improvement from the 4-1 first-leg defeat but it just didn’t happen on Wednesday night as the Poles ran out 2-0 winners.
The same things that went wrong last week went wrong again on Wednesday night.
Defensively Celtic were slack, they had no control from the midfield and there was no tempo to their play.
They didn’t create any chances and got what they deserved again. The two games were pretty similar and by no means good enough.
Not many people would have backed Celtic to go through the other night, but you would have thought they would have given themselves a better chance, questioned Legia more and won the game. But that wasn’t the case.
Warsaw were as comfortable in the second leg as they were in Poland, and when they got the first of the night it was over. It was a dispirited performance when so much more was expected of Celtic.
THAT is a worry for me. Ronny will now have to pick himself up and, more importantly, pick the team up.
I think you can question the spirit of the side. When you play for Celtic, you need to have a greater spirit than if you are playing for some other clubs.
Ronny will need to up the feeling and determination in the squad because it seemed to be missing against Legia. The manager will need new players this month, additions have to be made to boost the quality in the squad. But one of the big things he has to work on is the mentality of the players.
Whatever players you have got or formation you use, you need to have a bit of spirit and passion about you.
Aside from poor defending and the mistakes they made, that was an alarming aspect of the tie for me.
It is one that has to be rectified quickly. If you don’t and there is a lack of spirit, and it didn’t look like they were playing as a collective unit either, then even Premiership games can become a problem.
Ronny has to get that spirit back into the team fast or there could be problems in the Premiership, which people think is already done and dusted.
The league campaign will kick off next midweek away to St Johnstone and that will give Celtic a chance to regroup and start again.
There is still plenty to play for – there could even be Champions League group stage football – and the manager, players and fans have to remember that and remain positive going forward, no matter what competition Celtic are in.