As the clock ticked down towards 11pm last Friday and Big Ben got set to chime and signal the closure of the January transfer window, Hoops fans were left to watch the action unfold on TV through their fingers.
Just hours after celebrating the arrival of Leigh Griffiths, and seeing their new strike star paraded in front of the cameras and perform the obligatory ball-juggling on the hallowed turf, the news the Parkhead faithful were fearing was confirmed as Joe Ledley clinched his move to Crystal Palace.
Having held on to the midfielder for all but the final few minutes of the window, and had their hopes raised in recent weeks that he would commit his long-term future to the club, Ledley's departure was a sour way to end what has been another productive month of wheeling and dealing in the transfer market for manager Neil Lennon.
As the contract that lay on the table for several weeks remained unsigned, the fear for Celtic was that Ledley's seemingly inevitable departure in the summer would be brought forward by several months.
In the end, the Hoops elected to cash in on one of their top talents. The prospect of banking Palace's cash now rather than losing the midfield maestro for free later this year, made sense from a financial point of view.
And, if Hoops fans are honest and look at the bigger picture, it was the right call from a football perspective as well.
In Stefan Johansen, Lennon already had Ledley's replacement bought and in situ at Parkhead, the £2million acquisition from Norwegian champions Stromsgodset his largest outlay of the January window.
Like every manager, Lennon, in an ideal world, wants as many quality players at his disposal as possible.
Keeping Ledley at the club while Johansen got accustomed to life in Glasgow would have been the perfect scenario but, unfortunately for the champions, that chain of events would not unfold.
"I was disappointed to lose Joe," Lennon said after seeing his side stretch their advantage at the top of the Premiership standings with victory over St Mirren on Sunday afternoon.
"He was a superb player for me, really consistent and really good in the dressing room as well.
"It was a wrench to see him leave but we are hoping that Stefan can come in and fill that role now.
"It is the way these things go, a lot of business is done on the last day. We didn't want him to run his contract out.
"We had an offer on the table to him and he wasn't forthcoming in signing it. We have to move on."
While Lennon was undoubtedly frustrated at losing one of his most reliable and trusted performers as his side gear up for a crucial few months that will see them bid for Premiership and Scottish Cup glory, his pain would have been eased with the showing of new Bhoy Johansen at the weekend.
Handed his first start in the famous green and white hoops following a substitute appearance against Kilmarnock last midweek, the Norwegian certainly caught the eye with an accomplished display.
Partnering captain Scott Brown in the middle of the park, the man capped at seven different levels by his country, including six times for Per-Mathias Hogmo's full squad, was awarded the man of the match champagne after a calm and composed 90 minutes.
It is only a matter of time before Johansen will toast title glory when Celtic clinch three-in-a-row and Lennon is confident his new star can quickly step into the fold as the Hoops eye a second successive league and cup double. The manager said: "I was pleased with Johansen on Sunday, I thought he was outstanding.
"It was a terrific first start and he has set a really high standard for himself.
"He needs a bit of work but I am really pleased to have brought him to the club. He will score goals here and do well for us.
"In Stefan, we have found a really good player.
"It was as good a debut as I have seen in my time as manager.
"There was lots to be delighted about."
Johansen may have taken home the sponsor's bubbly and had the praise of his manager ringing in his ears as he left Parkhead, but he was not the only Celt to star on Sunday as St Mirren became the latest team to be swept aside on the champions' cruise to the Premiership crown.
As Kris Commons netted his 22nd goal of a superb campaign, the Hoops' lead was stretched to 21 points and their record-breaking clean-sheet run extended to 11 games.
They may have not added a shine to the scoreline to undermine their dominance, but there could be few complaints come the end of another satisfying 90 minutes for everyone in green and white as they prepare to take a break from league duty and put their run on the line against Aberdeen in the Scottish Cup this Saturday at Parkhead.
"I don't think you can complain about the performance," Lennon said. The football we played was very good.
"It wasn't like when we were winning 1-0 round about Christmas time and we were grinding out results.
"On Sunday, we were free-flowing and some of the football and attacking play was very good."