Celtic were 45 minutes away from clinching the championship after Tommy Johnson broke the deadlock against St Mirren.

Somehow Saints had been hanging on as chance after chance came and went but Johnson's strike put the party plans back on course.

Celtic manager Martin O'Neill was able to field an unchanged team as his team sought the three points that would see the Scottish Premier League title clinched convincingly early in his first season in charge.

The side that forced its way past Dundee in midweek was the one sent out with instructions to finish the job at the expense of bottom club St Mirren.

With Chris Sutton still suspended, Johnson continued his partnership up front with Henrik Larsson.

The Swede began the match a goal short of equalling Charlie Nicholas' post-war club record of 48 goals in all competitions.

And two today would see him equal Brian McClair's best ever Scottish Premier League haul of 35.

Saints arrived at a Parkhead full house still searching for their first away win of the season.

Indeed, they had only avoided defeat once on their travels, drawing at fellow strugglers Dundee United.

Manager Tom Hendrie selected an attacking line-up in a bid to pull off the shock result only the most die-hard Buddies fans were thinking was possible.

Steven McPhee, the on-loan striker from Coventry, was given a start, as was Jose Quitongo. Graham Fenton, largely ignored by O'Neill when both were at Leicester, was another attacking option for the visitors.

Top-scorer Ricky Gillies was another starter, disproving suggestions that he would be rested to avoid a yellow card that would have seen him suspended for a future relegation clash once the league splits in two next week.

Celtic worked the first chance of the match in the third minute when Paul Lambert strode into the box but Ricky Gillies timed his challenge perfectly to rob the Scotland international.

Then Johnson scuffed a shot wide from the next attack.

Sergei Baltacha held Alan Thompson back and from the free-kick Didier Agathe hooked the ball back into the area and Saints had to concede a corner that fell to Ramon Vega close in.

But he could not connect properly on the turn and the chance was gone.

Gillies fired Saints' first reply, an effort from outside the box that dipped but cleared the bar.

Scott McKenzie tripped Lubo Moravcik just outside the area but Larsson's free kick hit the wall.

Lambert beat Scott Walker in the box and it needed Barry McLaughlin to hack clear, almost in his own goal, for a corner that saw Johan Mjallby head over.

Saints were already having to soak up great pressure.

Lambert sent Moravcik away down the left and he cut inside to reach the box.

Ludovic Roy parried his shot and from the corner Vega and Mjallby both got touches, with the ball bouncing just wide for a goal kick.

Chris Kerr was booked in the 17th minute for a bad tackle on Agathe and from the free-kick Vega and Mjallby both went close to getting a touch.

Vega robbed Fenton to set up Moravcik for a low drive that went just wide of Roy's right-hand post.

Fenton lost possession just inside his own half and straight away Neil Lennon fed the ball down the middle to send Johnson through.

In came the shot but Roy had been quick to come off his line to block and the best chance so far was gone.

Moravcik again worked his way into the box and set up Johnson for a shot from an angle that skimmed across goal and was just inches wide.

Moravcik had a go himself but again the shot was wide of the target.

Celtic had created plenty of chances - but none had fallen to Larsson. His was the next shot but it was straight at Roy from outside the box.

Lennon set up Johnson for a shot once the striker had got away from McKenzie but again Roy pulled off a save.

Agathe beat McPhee to plant a cross on Moravcik's head but again the ball flew wide.

Then Moravcik sent Larsson through and he took the ball past Roy. But he had been forced too wide to the left and Roy was able to dive to stop his shot reaching the target.

Saints cleared the corner and counter attacked to send Fenton away but his shot was off target, with McPhee free in the middle.

Agathe's cross was almost turned into his own net by Jamie McGowan's sliced clearance and when Roy flapped at the corner it fell to Vega but he miskicked at the vital moment.

In the 38th minute Celtic finally broke the deadlock when Larsson unselfishly set up the unmarked Johnson in the box.

His first touch was not good but he recovered to slot the ball under Roy and in off Walker as the defender tried to block on the line.