Sunday is a day of rest, but not when there is a championship to be retained. Celtic waited 87 anxious minutes before the belated arrival of inspiration. It emanated from a predictable source but in circumstances that left St Mirren aggrieved.

For one brief, delightful moment, Shunsuke Nakamura lifted Celtic beyond the mediocrity in which they had been mired. The awarding of a free-kick in an area of prime real estate for the Japanese was, according to popular opinion at Love Street, less inspired than the finish.

Eddie Smith, the match referee, blew in Celtic's favour after Nakamura flopped down under a seemingly purposeful challenge from Gary Mason. Almost inevitably, Nakamura arced the ball beyond Mark Howard's groping hand and expertly inside the goalkeeper's left-hand post.

In rescuing Celtic, Nakamura prevented the champions slipping six points behind their Old Firm rivals, Rangers, at the top of the Clydesdale Bank Premier League.

The paucity of Celtic's play hinted at a communal bout of post-traumatic stress after the Champions League exhibition from Barcelona. It was not so much a hangover as a come-down. Such resilience is the hallmark of champions but Gordon Strachan will not be blinded by the recovery. Frailties remain apparent in the make-up.

Had it not been for the intervention of Artur Boruc, St Mirren could have recorded their first victory over one of the Old Firm since 1991. Few could have begrudged them such extravagant spoils. The Pole saved defiantly from David van Zanten and Billy Mehmet and kept together a ragged defence that was shorn of Stephen McManus for the final 38 minutes. By comparison, it took the visitors 50 minutes to test Howard and another 37 to finally beat him.

Fear of reprisals prevented Gus MacPherson from lending his view to the free-kick debate but the St Mirren manager ought to be commended for his outlook yesterday.

He is, after all, arguably the most under-appreciated manager operating in the Premier League. He has preserved the Paisley side's top-flight status on an annual budget that would not fund Scott Brown's services for six months.

The necessarily dour nature of St Mirren's perennial struggle has been received with a degree of apathy that suggests an element of the supporters would rather contest a first-division title race every year than savour the monotony of life on the lower rungs of the top tier. Yesterday provided fresh evidence of MacPherson's tactical evolution.

Against an uninspired Celtic, St Mirren's contribution was considerably greater than hapless sparring against the champions. Howard had no need to moisten his gloves in a redundant first half, his inactivity down as much to the security offered by the burly, shaven-headed doorman, Will Haining. The former Oldham centre back not only resisted Celtic's disjointed attacks but recycled possession efficiently.

Ahead, Andy Dorman and Mason formed a complementary midfield partnership of skill and will respectively. In Dorman, St Mirren had the most effective player afield. Their buzzing industry was the latest irritation for the forlorn Massimo Donati. Exemplary against Hearts, benched for Barcelona and anonymous at Love Street, his first public admission of assimilation problems in Scottish football had an ominous ring.

MacPherson's strategy was spearheaded by another contrasting pair. Mehmet's agricultural durability is almost traditional among provincial clubs in Scottish football. His endeavour and no little brawn unsettled a Celtic defence seemingly haunted by the vivid recollection of Henry, Messi and Ronaldinho dancing their way destructively.

Mehmet and Craig Dargo may be small fry by comparison, but they showed a similar willingness to inflict damage on Artur Boruc's goal, if only possessing a fraction of Barcelona's wherewithal.

Nakamura's intervention at least eclipsed the unsavoury contribution from an idiotic element of Celtic's away support, who seem to regard Love Street as a favourite venue in which to tarnish the club's otherwise excellent crowd record.

The songbook was distasteful at best and sectarian at its worst. In a five-minute burst during one of the many lulls in Celtic's play, they chanted about how Artur Boruc hates the Huns', made reference to orange bastards' and mocked the sectioning of Paul Gascoigne under the Mental Health Act with chants of let's all laugh at Gazza' and Gazza's a psycho'.

The effort expended chasing Barcelona's graceful shadows was apparent in Strachan's team selection at Love Street. Injury deprived the manager of Jan Venengoor of Hesselink. The loss of the reinvigorated Dutchman - 14 goals and counting this season - was soothed, at least on paper, by a summons for the impressive cameo performer, Georgios Samaras. The Greek's mobility was a feature of Celtic's otherwise unkempt play but too often Samaras's penetrative running occurred without the ball ever arriving in the vicinity of his dayglo orange boots.

Nakamura's subdued display midweek merited his demotion to the bench. Moreover, a drizzly Sunday slog against a team manfully scraping their way to Premier League safety is hardly an environment conducive to Nakamura's craft. He emerged for a late salvage job of immeasurable importance.