IF it had seemed like tempting fate when Ronny Deila spoke in the build-up about Celtic having good momentum following the international fortnight then his players did not make him look foolish.

The enforced break clearly made little difference to the champions-elect as they continued their relentless charge towards the title. It was not their most fluent performance but once they had gone in front against a St Mirren side wed to the foot of the table there was only going to be one outcome. Throw in another clean sheet and there was plenty for Deila to be happy about.

Celtic have blown teams away at times this season but they had to be patient here before eventually easing to what was a relatively comfortable win. It took two second-half goals - a James Forrest shot, and a Stefan Johansen penalty - to eventually break St Mirren down, and had the effect of taking them eight points clear at the top of the SPFL Premiership, throwing down the gauntlet once more to Aberdeen who face Partick Thistle this afternoon. The Firhill side, in fact, are also Celtic's next opponents in midweek as Deila's side motor ever closer to a fourth successive league title and the second part of the treble.

A St Mirren victory on Easter weekend would have had fingers tapping eagerly over keyboards about the Paisley side being "resurrected" or "coming back from the dead" in their quest to avoid relegation, but it wasn't to be despite them putting up solid resistance for large swathes of this contest. They remain with just one home league victory to their name all season and very much up against it as they look to avoid dropping into the second tier for the first time in nine years, lying four points adrift of second-bottom Motherwell who they meet at Fir Park on Tuesday night in what is shaping up to be a season-defining contest. Lose and it could well be all over before the split.

They may take some comfort from the manner of their performance in the opening hour when Celtic struggled to get properly into their stride. St Mirren started in a defensive fashion - Jim Goodwin was deployed as an effective buffer in front of the defence - and then retreated deeper and deeper towards their own goal, inviting their opponents on to them. Celtic did not need to be asked twice but couldn't initially get into the kind of rhythm that had helped them dismantle Dundee United so convincingly in their last outing prior to the break. With Nir Bitton fit enough only for a late run-out from the bench, Johansen, so often the main creative outlet for Celtic this season, was pressed into service in a deeper midfield role alongside Scott Brown. In attack there was a rare outing in the centre forward role for Anthony Stokes, selected ahead of Leigh Griffiths and John Guidetti. There was still plenty of running and talent in the Celtic front four but, for whatever reason, by half-time they had failed to break St Mirren's resolve. The home team had their goalkeeper to thank for that. Twice Celtic broke clear and twice Mark Ridgers was equal to it, pushing away Kris Commons' low driven effort and then repelling an effort from Forrest after the winger had drifted in from his wing to connect with a pass from Commons. Forrest also thudded a shot wide of target as Celtic struggled to find their feet.

St Mirren, scrapping for their lives at the foot of the table, had clearly decided there would be little shame in trying to dig in for a much-needed point, meaning there was little seen of them in an attacking sense. With John McGinn, Kieran Sadlier and Stephen Mallan offering nice touches in midfield, however, they still threatened in flashes. A Mallan header found its way into Craig Gordon's arms - he never really got a proper connection on it - while the same player hollered hopefully for a penalty after a collision with Stuart Armstrong. The loose ball rolled to Yoann Arquin but his tame effort dribbled straight to the goalkeeper.

St Mirren, perhaps surprised that they had reached the halfway point without conceding, began to show more ambition the longer the match wore on. They were hardly powering in shot after shot on the Celtic goal but they were seeing more of the ball and often diligent with it. Mallan and Arquin both attempted long-range efforts that failed to find the target but it was a sign that, perhaps, they had realised a victory might not be entirely beyond them.

That positive intent, however, left them more exposed whenever Celtic broke forwards. Stokes jabbed a shot at goal that Ridgers saved easily, while a ricochet off defender Jason Naismith almost looped over his own goalkeeper. Celtic's building frustration, however, would be assuaged when they finally moved in front after 64 minutes. Scott Brown started the move with a terrific ball wide to Adam Matthews whose cross was carefully placed beyond Ridgers by Forrest. It would prove to be Matthews' last involvement in the game, Deila perhaps grateful he hadn't put on Efe Ambrose moments earlier as the substitute waited on the touchline.

A second goal after 78 minutes ended any doubts over the outcome. Forrest's shot struck the outstretched arm of Viktor Genev and referee Alan Muir had no hesitation in awarding the penalty. Genev's sustained protests earned him a yellow card and Johansen calmly rolled in his kick. Celtic inch ever closer to the title.