For all of an hour in Perth, the dreamers could contemplate the possibility that Celtic's assault on a clutch of achievements had at last met an irresistible object in the form of Tommy Wright's defiant St Johnstone side, who had come from behind to post a merited lead over the runaway league leaders.
Celtic's customary opener, scored by Liam Henderson, had been cancelled out by Keith Watson's powerful header and then overtaken when Dedryck Boyata diverted a Danny Swanson cross into his own net to give Saints a half-time advantage.
They were undone, however, by a rare blunder on the part of referee Craig Thomson, who judged that a cross from Patrick Roberts had been handled by Watson in the box.
Watson and his colleagues berated the referee and their indignation was justified, with TV replays showing clearly that the ball had struck Watson's hip before his hand.
Ignoring the commotion, Moussa Dembele converted from the spot.
Dembele, who had been on the field for all of two minutes before finding the net, went on to achieve a hat-trick and Celtic's margin of victory was too substantial to justify feelings of injustice.
However, it left Wright and his players with a sense that they had been dealt a low blow at a crucial point. The fact they were denied a penalty of their own just before Dembele's intervention, when Paul Paton went down under pressure from Scott Brown, only inflamed matters.
"I am not going to sit on the fence," Wright told BBC Scotland afterwards. "When Brown makes contact, that's a penalty, and he doesn't give it.
"Then Joe Shaughnessy is dragged down when the ball is in the air in the penalty box.
"As for Celtic's penalty, I genuinely don't know how he could give it. It has hit his (Watson's) hip and could have touched his elbow, but I don't know how he couldn't have seen it.
"Granted, Celtic could go on to win the game without that decision as they have so much talent, but the decision changes the whole dynamics of the game. "
Brendan Rodgers backed Wright.
"I sympathise with Tommy," the Celtic manager said. "I've seen some funny decisions up here. These are part-time guys thrust into high-pressure games."
Henderson's opener just past the half-hour mark finished a passage of intense Celtic pressure when he drove home the rebound from a Roberts effort blocked by Zander Clark, but Saints responded when Watson met Swanson's corner kick with a fine header which Craig Gordon reached, but could not stop.
The oddity was that Henderson's goal was his first for Celtic since January 2015, while Watson last found the net as a Dundee United player in September 2014.
There was debate about the next goal which appeared to come off Boyata from a Swanson cross in the 39th minute, although the Hoops defender was content to let David Wotherspoon claim the credit for what proved to be the high-water mark of Saints' fortunes.
Once Dembele made it 2-2, the contest moved steadily in Celtic's favour.
Dembele added two more and Scott Sinclair took his total for the season to 16.
Celtic moved a staggering 27 points clear of Aberdeen with their 29th successive unbeaten domestic fixture, 23 of which have been victories.