Even a second successive victory in the fixture for Gordon Strachan's team would make little impact on the bookmakers' offer of 1/4 about ultimate success for Rangers.

Walter Smith's side could even afford to lose again on their run to the line and still finish a point ahead of their great rivals.

Anything less than three points for Celtic, however, would almost certainly turn them into immediate past champions. As Strachan himself observed yesterday, "A win for us would simply keep the league going for another week. That's as much as we can look for at this moment."

The Celtic manager had concluded some time before Rangers' visit to Parkhead 11 days ago that his own team would be required to take maximum points from their remaining six matches to have even the semblance of a chance of keeping the title that has been in their possession for the last two years.

Fulfilling their need in the first three of those assignments – away to Motherwell and at home to Rangers and Aberdeen – has done nothing to alter their imperatives, but merely prevented the object of their pursuit from disappearing over the horizon.

Nonetheless, that winning treble in the space of a week has catapulted Celtic into a two-point lead – Rangers having played three matches fewer – and given an edge to a fixture which, like an everlasting razor blade, requires no sharpening.

The feverishness that almost invariably descends on the match was evidenced at the finish of that last encounter, when several players became involved in some largely non-threatening scuffling – most people will have seen more convincing fights in school playgrounds – that led to a central defender from each side, Gary Caldwell and David Weir, being summoned to referee Kenny Clark's room a week last Wednesday and given the equivalent of a red card.

Strachan hinted yesterday the raised tempers on that occasion had come as a surprise, as it had seemed to him that much of the old ferocity had gone out of the game.

"My impression of Old Firm matches when I first came back to Scotland three years ago was that they had become quite sanitised," he said.

"But, in more recent times, there has been a return to something like the high tension of the 1980s, when I played here. Maybe it has become more localised again, with so many Scots in the two teams now.

"Of course, you'd rather the players channelled their aggression in the right way, in a way that will help win the match rather than bring trouble at the end of it. More than anything, you want to play better in each game than the one before, you have standards you want to be reached. That's what gives you a chance of winning.

"For us, the way things are, the priority is simply to win the game. We've got ourselves behind, in terms of points dropped over the season, as a consequence of our own play and, of course, Rangers' consistency."

Despite a competent performance from Bobo Balde in the 1-0 victory over Aberdeen last Saturday, Strachan seems very likely to restore Caldwell, free of suspension, to the central defence beside Stephen McManus.

Indeed, even with midfielder Scott Brown available after serving a three-match ban, he gave the impression he would favour fielding the team who beat Rangers 2-1.

But he will have to await a health report on Shunsuke Nakamura, the Japanese midfielder – scorer of the blistering opening goal against Rangers – having been afflicted by a virus that caused him to miss training.

"Naka had had an ankle problem, but that's cleared up now," said the manager. "We'll see how he is tomorrow, but he has a chance of playing. The other injured players all trained and are all available."

Strachan clearly has wider options than Smith, who must compensate for the suspensions of Carlos Cuellar and Kevin Thomson, and the injury-enforced unavailability of Lee McCulloch and several others, such as Steven Naismith and Chris Burke, who would probably have been at least on the bench.

Neither side ever goes into an Old Firm match without pressure, but the vulnerability of Celtic's position – with victory essential, as opposed to preferable – makes their burden a little heavier than that of Rangers.

That could be offset by being at home, an almost tangible advantage in these circumstances.

The debate generated by the SPL's alternative schedule for the remaining fixtures may bring another source of heat to a potentially inflammatory occasion, but it is one into which Strachan merely dipped a small toe .

"I'm just a manager," he said. "I'll play whenever I'm told I have to play. I was the same as a player, it didn't make any difference what day of the week I had to play.

"I know we have players going off on international duty at he end of the season, but, if there is a four-day extension, I don't think it will have much of an effect.

"It's going to be a long summer for the guys on international duty in any case, and I think modern players at that level have to accept that the game nowadays is just about an all-year long occupation."