Match ends, Celtic 3, St. Johnstone 1.
Celtic moved six points clear at the top of the Scottish Premiership with an assured victory over St Johnstone.
The defending champions were efficient as they took control with first-half goals from Gary Mackay-Steven and Stuart Armstrong.
St Johnstone briefly rallied, and tied the game at 1-1 when Steven MacLean equalised.
But they had no answer to Celtic's growing authority and Mackay-Steven netted again after the break.
Leaders too strong for Saints
St Johnstone's resistance lasted only nine minutes, though they may consider that a feat given how ruthlessly Celtic dispatched Hamilton 8-1 in midweek with three early goals.
Few defences have found the means to curtail Leigh Griffiths this season and, after his effort was blocked, Mackay-Steven darted through to drive past Alan Mannus.
The visitors from Perth did not allow their sprightliness to be subdued by the circumstances and Michael O'Halloran's pace could not be contained.
He may yet complete a move to Rangers but he was focused in Glasgow and skipped past Kieran Tierney to cross for MacLean to finish from close range.
Frustration might have set in for the home side but Armstrong was brilliantly accurate and composed as he swept a first-time volley into the net from Mikael Lustig's cross.
Another goal after the break finally quelled St Johnstone's spirit. Johansen's pass might have been aimed at Griffiths, but the ball fell perfectly into Mackay-Steven's stride for him to finish with cool aplomb.
Youngsters on form
The display was sound from Celtic and scattered with the promise of their youthful attacking players.
Though over elaborate, Celtic dominated possession and Mackay-Steven, Griffiths and Callum McGregor all impressed in the final third, while debutant Ryan Christie replaced Armstrong late on.
The standout Celtic player was Tierney, though, who played with a depth of composure and awareness that sets him apart in defence and attack.
There were other half-chances, so that the scoreline might better have reflected Celtic's hold in the game, but also a clearance off his own goal-line from Johansen.
St Johnstone never lost heart, but the gap in quality could not be breached.
- 42McGregorSubstituted forAllanat 79'minutes
- 16Mackay-StevenSubstituted forForrestat 86'minutes
- 14ArmstrongSubstituted forChristieat 88'minutes
- 14ShaughnessyBooked at 45mins
- 8DavidsonBooked at 45minsSubstituted forCaddisat 69'minutes
- 18CumminsSubstituted forCraigat 45'minutes
- 9MacLeanSubstituted forSuttonat 65'minutes
- Kevin Clancy
- Shots on Target
Second Half ends, Celtic 3, St. Johnstone 1.
Foul by Ryan Christie (Celtic).
Liam Craig (St. Johnstone) wins a free kick in the defensive half.
Substitution, Celtic. Ryan Christie replaces Stuart Armstrong.
Attempt missed. Michael O'Halloran (St. Johnstone) left footed shot from the centre of the box is close, but misses to the left.
Substitution, Celtic. James Forrest replaces Gary Mackay-Steven.
Foul by Scott Allan (Celtic).
Joe Shaughnessy (St. Johnstone) wins a free kick in the defensive half.
Attempt saved. David Wotherspoon (St. Johnstone) header from the centre of the box is saved in the centre of the goal.
Attempt saved. Leigh Griffiths (Celtic) header from the right side of the six yard box is saved in the bottom right corner.
Substitution, Celtic. Scott Allan replaces Callum McGregor.
Attempt missed. Callum McGregor (Celtic) left footed shot from the left side of the box misses to the right.
Attempt saved. Gary Mackay-Steven (Celtic) left footed shot from the centre of the box is saved in the centre of the goal.
Foul by Jozo Simunovic (Celtic).
Michael O'Halloran (St. Johnstone) wins a free kick in the defensive half.
Foul by Leigh Griffiths (Celtic).
Tam Scobbie (St. Johnstone) wins a free kick in the attacking half.
Attempt missed. Brian Easton (St. Johnstone) left footed shot from outside the box is too high.
Foul by Nir Bitton (Celtic).