Had Dick Advocaat's side lost that one, it would have been a case of last man out the ground put the lights off.
Those who ally themselves to Celtic Football Club as players, supporters or shareholders awoke to headlines on Monday morning suggesting that their world had ended.
It may even have been mid-morning before they realised that the east end of Glasgow had not been taken over by aliens and neither were the sherriff's officers at the door.
The bad news from their perspective was that their team had indeed been dismantled by their oldest rivals at Ibrox. The good news was that the damage was far from terminal.
I was slightly confused as to why, at full time, the players of Rangers saw fit to take an ovation, although they did have the decency to stop short of a lap of honour.
And, before you ask why, please let me explain.
Sure they won...but, at the end of it all, the highest-paid group of players in this country still trail the championship leaders by 12 points, sit third in the table and for them the Champions' League is still a memory.
Rangers are still guilty of under-achieving, despite Sunday's result, although it was inconceivable to me, as regular readers of this column will know, that they would lose at the weekend.
Had Dick Advocaat's side lost that one, it would have been a case of last man out the ground put the lights off.
The champions threw £12m on the table to save their title. So far, the gamble has worked, but all they have won is the first hand of poker.
Celtic, when all is said and done, still sit in control full in the knowledge that if they turn over everybody else in the league then, no matter what happens in the remaining Old Firm encounters, the jewel in the domestic crown is theirs.
I enjoyed the match. Kenny Clark made a couple of mistakes, but basically he had a good game.
The truth is that, until the good Lord takes it upon himself to referee an Old Firm fixture, there will always be mumping about the performance of the match official.
In all my decades of covering the fixture, I can't remember one game when both sets of supporters roundly applauded the performance of the man in the middle.
Still, maybe one day. After all, there was hope for the great divide at the weekend coutersy of the Rangers fans who hung a huge banner from the main stand that declared :"Good luck, Alan Stubbs." Excellent.
The free-kick that led to the opening goal was taken about 10 yards from where the offence occurred, but there was much football played before the ball ended up in the Celtic net and they should have been alive to the fact that play was raging on.
And another thing. Players and fans are the first to moan at refs who insist that free kicks should be taken from the very blade of grass on which the foul was committed.
Clark was performing in the spirit of the game, which insists that, at all times, we should keep play flowing.
I can't believe how nervous Celtic fans have suddenly become. If they beat Hibs on Wednesday night, the gap goes back to 15 points and it could be 18 before Rangers play against Hearts on Sunday.
Crisis? What crisis?