Celtic would streak from third place to top of the Premier Division tonight if they beat Aberdeen at Parkhead by six goals. Given the new significance of the match and its attendant pressures, however, they will settle for a single-goal win.

Only 48 hours ago, nobody connected with Celtic would have believed that the visit of the Pittodrie side, live on Sky, could have held such opportunity. It was expected that Saturday's programme would end with Rangers enjoying a six-point advantage, with Wim Jansen's side merely looking for a victory that would keep the deficit manageable.

But the champions' 2-0 defeat at St Johnstone and Hearts' 2-0 victory over Dundee United has brought a new tightness, with the previously unimagined possibility of a three-way tie at the top. Celtic are long odds-on, with Aberdeen around 6 to 1, for tonight's game, but the home side have demonstrated often enough this season a dangerous capacity for faltering when least expected.

With around 50,000 in support - live television does not interfere with attendances at the Old Firm's home games these days - they should certainly not lack a sense of urgency. And if they can reproduce the fluency of which they have frequently shown themselves to be capable, they should capture the three points.

It is Rangers' apparent loss of appetite that is worrying Walter Smith. After John O'Neil and George O'Boyle had secured St Johnstone's first victory over the champions in 26 years, the Ibrox manager expressed his anxiety.

"We've had two bad performances in a row now, this one and the Scottish Cup tie with Hamilton last week," he said. "We seem only to react when the other team have gone ahead and that's worrying."

There is also concern about Paul Gascoigne, who, Smith revealed, has been bothered by a groin injury throughout the season. He was a substitute once again at McDiarmid Park, coming on only after St Johnstone were ahead.

"After he played last week, he couldn't train for three days," said Smith, "so maybe we'll have to be a bit more careful with him. Of course, getting Gascoigne right and playing as he can would be a boost for any team."

Hearts' persistent challenge to the Glasgow giants shows little sign of waning. The double from Colin Cameron - one in each half - that brought victory over United was the latest evidence of their tenacity. They are at home to Celtic on Sunday and victory for the Parkhead side tonight would make tickets for that encounter as precious as platinum.