Kris Commons' goal against St Mirren gave Celtic their 14th consecutive win, extending their Premiership lead to 21 points.
Commons netted his 22nd goal of the campaign, beating goalkeeper Marian Kello from distance in the first half.
The Hoops dominated and could have made the score-line far more convincing as they passed up several opportunities.
Celtic goalkeeper Fraser Forster was rarely troubled and made a club-record 11th consecutive shut-out.
The Saints stay in ninth position and are increasingly becoming embroiled in a relegation play-off battle.
Having met earlier in January and the Hoops running out emphatic 4-0 victors, it was more of the same at Celtic Park as Commons once again proved irrepressible.
The attacker's influence was felt as early as the sixth minute as he received a pass from Emilio Izaguirre, glided away from Jim Goodwin before powering an effort from distance that Kello was unable to keep out.
That set the tone for a one-sided encounter and, while Neil Lennon had said before the match that it was a "free game" for the visitors, it was the hosts who were playing free-flowing, slick and entertaining football; the type you would expect from a side with an 18-point lead at the top pre-match.
It was the 18th-minute that home supporters demonstrated their solidarity for Lennon, who was targeted by fans at the League Cup semi-final yesterday.
However, before that, the impressive Virgil van Dijk showed his strength and balance, holding off a couple of Saints players before releasing Anthony Stokes, whose dinked effort went narrowly wide.
The Irishman was clearly determined to make his 100th appearance for the club memorable and fashioned an opportunity for himself, pirouetting before sending an effort clear of the target as Celtic looked to turn their domination into a sizeable lead.
Lennon's men were unrelenting and Scott Brown could have doubled the hosts' advantage, but fired over the bar after tidy work by Commons.
A brief reprieve for the Saints saw former Rangers man Gregg Wylde latch onto a long ball and test Forster, but the shot-stopper was untroubled, before more Celtic pressure resumed.
Stefan Johansen, making his first start for the club, created an opening but could not execute the shot properly, before James Forrest cut inside and fizzed a low shot that Kello had to get low down to save.
The one-way traffic continued after the break as Buddies defender Marc McAusland almost put into his own net following Charlie Mulgrew's centre.
St Mirren's forays into champions' territory were few and far between.
Steven Thompson did attempt to be a nuisance, forcing Efe Ambrose to clear hastily; while debutant Josh Magennis warmed the palms of Forster with a stinging shot.
However, the Saints had to be aware of the threat at the other end, with Forrest unable to convert the couple of chances that came his way.
Adam Campbell was flung on in place of Goodwin as St Mirren searched for an equaliser, but it was the hosts who looked more likely to add to their lead, with substitute Amido Balde coming close, before Stokes rounded Kello and missed.
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