Celtic moved into a threeway share of the Scottish Premier Division lead with a victory that was as predictable as it was ultimately comfortable. When the substitute Darren Jackson whipped a close-range shot high past Jim Leighton near the end, he merely confirmed a superiority that had been growing in the Celtic team since they conceded an early opener to David Rowson.Celtic have recently developed the worrying habit of conserving their sense of urgency and their quick and deadly movement until after the opposition have gone ahead.They did it again last night, less than a week after allowing Dundee United the same first-half luxury. But this time the Parkhead side asserted themselves so quickly after Rowson's opener that they were ahead before half-time.They also managed to shake the frame of the goal twice during a period of aggressiveness that brought a mixture of sound finishing and bad luck. During those earlier minutes, however, their lethargy almost allowed Aberdeen to establishwhat could have been a telling advantage.Not only did Rowson score after eight minutes, but Mike Newell's quick, powerful header forced Jonathan Gould into an extraordinary save soon after. All of this before Morten Wieghorst equalised and Henrik Larsson gave the home side the lead.Rowson's goal was bedecked in good fortune, his 25-yard drive following a corner on the left taking a wicked deflection from Alan Stubbs and eluding Gould high to the goalkeeper's left. Stubbs himself had rattled Leighton's crossbar with a clean, powerful header from Jackie McNamara's corner on the right.McNamara followed with a 25yard drive that flew away to the right of Leighton but came back off the inside of the post before Wieghorst equalised in the 21st minute.Another McNamara cross from the right was knocked on to Wieghorst by Paul Lambert and the big Dane rolled the shot from 15 yards to the right of Leighton.Larsson finally put Celtic ahead 10 minutes before the interval with a six-yard header after Marc Rieper headed forward Stubbs's free-kick.Celtic's keenness to avoid a repeat of their slow start to the first half brought such a concentration of pressure early in the second that they would have been much further ahead but for Leighton's work.The goalkeeper managed to block Burley's low shot after the midfielder had been released on Larsson's dummy into an inviting position on the right side of the area. Harald Brattbakk took the loose ball and his chip would have counted, too, but for Leighton's leap to flick the ball over the bar.Before those incidents, McNamara had a bad miss. Larsson supplied Stephane Mahe on the left and the Frenchman's centre was so precise that McNamara had time to pick his corner before making the header. Calmly and deliberately, the midfielder put the ball back across the goal and wide of the far post.Before the match, Celtic managing director Fergus McCann warned his club's supporters that those who engage in bigotry will be barred from Parkhead.McCann issued the threat at the launch of `Youth Against Bigotry', part of the `Bhoys Against Bigotry' campaign.The Celtic chief is determined to educate fans of the future by the latest initiative which is targeting local schools.But McCann remains concerned with addressing those with more entrenched attitudes as he bids to make Celtic Park a sectarian-free zone.He said last night: "Because we have so many season ticket holders and sophisticated camera technology, it is much easier to single out individuals."