Leigh Griffiths scored a hat-trick as Celtic extended their lead at the top of the Scottish Premiership to 16 points after easing aside St Mirren.
Griffiths scored twice in the first-half - from Odsonne Edouard's cross, then after a one-two with Tom Rogic. Edouard netted before Griffiths' third while Callum McGregor converted a late penalty as Celtic edged closer to a ninth consecutive title.
Neil Lennon's side - who have played two more games than Rangers - have won 12 of their 13 domestic games in 2020.
St Mirren, meanwhile, slip to 11th and are now just three points clear of bottom side Hearts.
Any chance of a shock St Mirren victory looked slim. It is 30 years since the Paisley side had last won in the east end of Glasgow - a young Paul Lambert putting the final goal past Pat Bonner in a 3-0 win.
In the here and now, Celtic were aiming to go 16 points clear at the top for 24 hours at least, with St Mirren looking for anything to ease their relegation fears.
Although history hung heavy against the visitors, Jim Goodwin's side began the match well as they sported a sturdy back three with the wing-backs getting St Mirren up the field.
But one of those wing-backs - Calum Waters - switched off for a second and allowed Griffiths to ghost in at the back post to finish calmly from close range to make it 1-0.
That dented the confidence of the away side as Celtic began to pepper the St Mirren goal, Vaclav Hladky having to pull off a series of fine saves to keep out Edouard, James Forrest and Rogic.
Tony Andreu managed a swerving shot from 20 yards which Fraser Forster comfortably saved, but any chance of a St Mirren revival evaporated on the stroke of half time.
A wonderful moment of interplay on the edge of the box between Rogic and Griffiths put the Scotland striker in and he dinked the ball past Hladky to make it 2-0.
Getting anything from this match would have been a bonus for St Mirren, their impending midweek encounter against Hearts of greater import in terms of how this season pans out.
As for Celtic, this was all about ensuring no complacency crept in with such a massive gap over Rangers at the top of the table and a meeting with their city rivals at Ibrox next weekend.
Griffiths rifled in another shot which Hladky touched wide, but it felt almost inevitable Celtic would score again.
Edouard's footwork had been impressive all afternoon, and he turned neatly in the box before firing home with ruthless efficiency as the game ceased to be any kind of contest.
There was icing on the cake for Celtic and Scotland as Griffiths lashed home from the edge of the box to seal a fine hat-trick - taking his tally for the season to 11.
McGregor fired home a late penalty as Celtic ran out very comfortable winners.
Griffiths could not be coming to the boil at a better time, with Celtic closing in on a ninth title in a row, a showdown with Rangers next weekend, and massive matches for Scotland now only weeks away.
He looks sharp and hungry again, and that wand of a left foot will always be with him. The best compliment you can pay him is that he is now starting to look like the Griffiths of old.
Celtic manager Neil Lennon: "Leigh's been working hard since the beginning of the year. I'm just pleased for him personally.
"And I'm delighted for Tom Rogic. We've been rotating him and Ryan Christie and he shows great intelligence and great feet."
St Mirren manager Jim Goodwin: "We didn't really get close enough to Celtic, we didn't show enough aggression all over the park.
"Celtic are miles ahead of anyone in this league. It's quite scary really, they probably never got out of second gear this afternoon and still managed to put five past us so we've just got to take it on the chin."