The victories over Rennes and Motherwell have breathed fresh optimism into a club which had the wind taken out of it with a blow to the solar plexus when they failed to defeat Hibs at home and fell even further behind in the SPL title race.
Now the dark clouds which had been ominously gathering have been replaced by clear sky – and even clearer thinking.
The forecast for Celtic is brighter than it has been for some time as they prepare to resume action with a trip to Inverness followed four days later by the visit of Dunfermline for the outstanding fixture which will give them the opportunity to reduce the lead held by Rangers to single digits.
With a crucial Europa League tie against Atletico Madrid also on the heavily- congested schedule, the huge tests just keep coming.
But coach Alan Thompson believes they are now ready and willing to meet every one head on.
He said: "The good thing is we are going into this break on the back of two good results, against Rennes and at Motherwell.
"We can look forward to the Inverness game a week on Saturday knowing we are back in second place in the SPL and that we will have a few more of our players back from injury by the time that game comes around.
"We also know we have a group of players who are prepared to work their socks off for us."
That is the most re-energising bonus to emerge from the comeback victories over the French club and the team which had been holding second spot in the SPL.
At the heart of both impressive displays was Victor Wanyama, a 20-year-old new Bhoy who manager Neil Lennon singled out as "playing like a man."
As he headed off to represent Kenya in their World Cup qualifier double-header against the Seychelles, it was not just the prospect of playing in sunnier climes which should have given Wanyama a warm glow.
The midfielder bought from Belgian club Germinal Beerschot in the summer for £900,000 can reflect on making the breakthrough to become a regular first pick, and not just because so many competitors for places in that area of the pitch are out injured.
Wanyama has been on a massive learning curve since he made the move across the North Sea.
But the rate of his development has not surprised Thompson, who said: "I would not say Victor has progressed quicker than we thought he would because he is an international player.
"He has also played in the top league in Belgium.
"But he is still a young lad, and it is going to take him a little time to settle down, get to know us, to know the players, to know the environment and get to know the speed of the game here. It was the speed that caught him out most when he first arrived from Belgium.
"But the more he has trained with us, the quicker he has done things. And he is going to be a right good player."
Celtic's coaching team have fast-tracked Wanyama's education by putting him under intense pressure during training matches at Lennoxtown.
The intention is to simulate precisely what will confront him when the action is for real.
"We have done that because, when he first arrived, the training was quicker and the games were quicker and it took him a while to get there," explained Thompson. "But he is there now."
Now the challenge for Wanyama is to continue the improvement which has carried him this far.
He is showing a reassuring appetite to do just that and, in the Europa League ties in particular, has gone from strength to strength in his role protecting the vulnerable back four.
The partnership Wanyama is forming with Beram Kayal – although much more experienced, still only three years his senior – is a key plank in Lennon's game plan.
The manager understands the importance of having strong partnerships in vital areas of the park, and nowhere more so than up front.
So, it is with understandable relief that everyone at the club has been able to applaud the return of Anthony Stokes and Gary Hooper to the scoresheet in the games against Rennes and Motherwell.
Lennon had some very harsh words to say about the mis- firing duo after their no-show against Hibs at Parkhead 10 days ago.
Hooper paid the price by dropping out of the line-up for the tie against the French, but gave the perfect response when he came off the bench to hit the nerve-settling third goal.
However, even that was not enough to win him a starting place at Fir Park, although Thompson revealed an on-going fitness issue was also behind Lennon's thinking.
"Gary was feeling a bit tight," said Thompson. "He has had a couple of problems in the last couple of weeks.
"But he looked fresh when he came on against Rennes last Thursday, and we thought he might give us a freshness if we needed him to come on again against Motherwell."
Hooper certainly looked back to his best, with his work-rate returning to its previously high level.
What Hooper is battling is not unique, and is commonly referred to as second seasonitis.
When a debut campaign exceeds expectations, disappointment can often follow.
But Thompson can see the green shoots of recovery, and said: "Gary is another one who set really high standards last season, and he is getting back towards those standards at the moment.
"A lot of them set high, high levels last season, and we haven't quite got back to that. The consistency has not been there, but it's up to us as a management team to get them back up to that level."