McLeish was given a stay of execution last week by the chairman, David Murray, who told him that he was still the man for the job. The derby represented the first of three games to save his career, but goals from John Hartson, Bobo Baldé and Aiden McGeady tightened the noose around McLeish's neck.
Ironically, an end to his almost four-year reign at Ibrox was being hastened by his friend, and former Aberdeen colleague, Gordon Strachan, who now appears capable of filling Martin O'Neill's shoes. That McLeish's team have only won twice in the last 12 outings heightens the pressure before Wednesday's Champions' League match at Porto.
However, ambitions of being in Europe next season are in jeopardy. Rangers are behind Hibernian who are more credible challengers to Celtic and Hearts in the title race.
"Yes, I expect to still be in charge in Portugal," insisted McLeish. "The chairman has said he would look at things in December and I still want to be manager of Rangers." Roy Keane was conspicuous by his absence at Parkhead. The Republic of Ireland captain may yet get his first taste of Old Firm action when the sides next convene in February, now that he has parted company with Manchester United. However, on this evidence Strachan does not need him. Celtic's two Irishmen, Neil Lennon and McGeady, provided a zest in midfield that Keane would struggle to match.
"It's out of my hands," reflected captain Lennon. "If he comes, great. If not, then we will carry on regardless. However, whoever comes here will have to work very hard to get into this team. Fifteen points is a great cushion to have over Rangers."
Rangers, having lost here 10 days earlier in the League Cup, approached this with the frenetic desperation of condemned men and probably created the best chances in the first half.
However, once Hartson scored his 11th goal of the season after 12 minutes, an air of predictability clung to the contest. The Welsh striker profited when Shunsuke Nakamura seized on a bad pass from Alan Hutton and threaded the ball into Shaun Maloney, whose cutback was steered in by Hartson's right boot from 12 yards.
Celtic showed no such leniency in the second half as they scored twice within five minutes just before the hour mark. Nakamura tormented Ian Murray before delivering a cross in the 56th minute that was glanced beyond Ronald Waterreus by the fearsome Baldé.
Then Stilian Petrov cleverly held up play, awaiting the well-timed burst into the box from McGeady, whose right-foot volley squirmed past Waterreus's grasp. There was no way back for Rangers. The sight of their talisman Dado Prso sustaining a hamstring injury merely compounded a wretched afternoon.Reuse content