AN 18-point cushion at the top of the Clydesdale Bank Premier League does not just provide comfort for Celtic.

It will also soften the blow for St Johnstone should things not go according to plan this evening, when the Perth side step out in front of a title procession which is being carried out with all the subtlety of a juggernaut with faulty brakes; the league leaders having gone on a run of six straight league wins during which they have only paused long enough to score 26 times. They are not so much putting up the shutters at McDiarmid Park as bracing for impact.

Celtic are on a bit of a roll in the league then, and duly flattened Dundee United 6-2 at the weekend, even if such a result will come to be viewed in isolation. Jackie McNamara will have learned much about his United team during that match but the lessons will be more stringently applied in games against sides of similar standing, starting with Motherwell tonight. The outcome of that meeting will also be of interest to St Johnstone since all three clubs harbour ambitions of qualifying for Europe this season, and it is how they size up against one another which will deliver the true measure of their success.

St Johnstone have squeezed into the top six on goal difference, holding off both Kilmarnock and Aberdeen, and will be aware that they will be back among the qualification places for the Europa League should they manage a win tonight. Having already taken four points from Celtic this season, they perhaps have done more than most to upset the champions' momentum – a 5-0 defeat in the quarter-finals of the Scottish Communities League Cup aside – but Steve Lomas seemed intent not to rile the Parkhead side any further ahead of their arrival in Perth.

"Getting a result would be a bit like a bonus, in a way," said the St Johnstone manager. "But we want to go out and compete against them, and we have done in all but probably one game when they gave us an absolute doing in the cup. That was a bit of a backlash after Kilmarnock had just beaten them at home [in the league] so it wasn't really a great time to play them.

"Celtic can give anybody a doing; they have done it to us this season, they have done it to Dundee United and they will do it to others. That is just the calibre of the squad that they have got."

It seemed necessary to be blunt about his side's prospects this evening given that Celtic left little room for contention on Saturday. That result against United would not have looked any better from Dingwall, either – where St Johnstone lost narrowly at the weekend – even if Lomas could see injustice in the misfortune of his own side.

Playing down the chances of gaining some sense of redress by taking something against Celtic was also at odds with his competitive sensibilities and he was careful not to seem resigned to another going over by the Parkhead side.

"We want to go out and compete. If you don't have that in your make- up then you might as well not go out and play," he said. "Listen, to beat Celtic we are going to have to be at our best. There is no 'fear' about playing them – there is just a realisation that we have got to do well, both individually and collectively, to get anything. You don't play badly against Celtic and get anything; it's as simple as that there."