Billy Baxter's flag deprived Rangers a legitimate winning goal at Pittodrie. That it took until the 90th minute to find the net for a second time in a match the visitors dominated for large swathes is arguably of greater significance as the first Old Firm derby of a fledgling season beckons.

The assistant referee ruined DaMarcus Beasley's introductory swipe, as well as Craig Thomson weekend. The referee was blameless for the latest calamity for officialdom. If nothing else, Baxter brought enduring controversy to an uncharacteristically tedious meeting of two mutually contemptuous rivals.

Walter Smith, both diplomatic and dignified in his response to Baxter's error, was presumably as vexed by Kris Boyd's leisurely existence in an offside position as he was with the assistant's failure to determine active presence from inactive.

The incident has revived a tiresome debate on the merits of introducing video technology. FIFA will hardly be working themselves into a lather over a bout of refereeing incompetence in the outpost of Scottish football. Smith's task between now and Sunday afternoon's visit to Celtic Park is how to maximise productivity and minimise Rangers' tendency to leave victory to chance.

Aberdeen were rejuvenated by Rangers' inability to convert pressure into tangible reward. David Weir craned his neck to put the guests ahead after 24 minutes. Aberdeen equalised with the last kick of a monotonous first half and from their first serious venture forward.

On Friday, Ally McCoist expressed his preference for an established strike partnership, despite a glut of potential goal-getters. Boyd has been the only constant of an ever-changing domestic front line but in three games has found the net only once, from the penalty spot at that. The downside is that when Boyd's name does not appear in lights, he is otherwise anonymous.

He was partnered by Nacho Novo at Pittodrie but the Spaniard performed in a no man's land; buzzing around Boyd one minute and attempting to plug an obvious gap on Rangers' right hand-side the next.   Injuries have not helped his cause but Smith has developed a habit of utilising players outwith their established habitat. Kirk Broadfoot and Sasa Papac have already been converted into dependable, if hardly dynamic, full backs but width was compromised further by Steven Davis, a central midfielder, performing as an old-fashioned inside-right and Kenny Miller, a striker, running tirelessly - and largely pointlessly - on the left.

As a consequence, Rangers enjoyed a disjointed dominance while failing to turn their possession dominance into goals. Smith will return to the drawing board before a derby that, on last season's evidence, will be neither defining or decisive but will determine how well-equipped Rangers' new signings are for the Glasgow joust.

Pedro Mendes' subtle skills and simplistic influence featured prominently in a sprightly start at Pittodrie, while Davis offered a reminder of his drive and determination. It was around this axis that Rangers suffered. Novo is an impact substitute but in a rare start, showed the composure of a hyperactive child on the first day back at school.

Aberdeen were even less threatening. Gary McDonald and Mark Kerr were simply squeezed out by the superior class of Mendes and might of Davis, while Jamie Smith struggled for supply on the left.

Madjid Bougherra matched Darren Mackie's surging runs and, for the most part, David Weir dominated Lee Miller in the aerial joust. That was until the final seconds of a sterile first half. Charlie Mulgrew's cross from the left hung in the air long for Miller to fend off Weir, his header was beaten away by Allan McGregor but Derek Young's alertness enabled him to sweep the rebound high into the net.

If the 45 minutes ended in groans from the away section, they were apoplectic at full time. By then, Boyd had resorted to speculative efforts from 45 yards out, Jamie Langfield threatened one of his intermittent gaffes, and McGregor denied Mackie as Aberdeen began shelling from their own half.   Darcheville replaced Novo with 18 minutes remaining but that was barely enough time for the brawny Frenchman to warm-up his over-developed muscles. Beasley, waif-like by comparison, took over from Miller and stabbed home what he considered the winning goal from Mendes' marvellous cross. He did so as the Aberdeen defenders switched off: Boyd had loitered offside and, while not interfering, Baxter raised his flag. Thomson, who restricted his tidy business to a solitary booking for Tommy Wright, had no option but to trust his assistant.

The question for Smith is: who can he trust to make the correct decisions inside the penalty box for Rangers on Sunday?