Gordon Strachan will face the toughest challenge of his managerial reign at Celtic when the Glasgow club play host to their city rivals in a crucial league encounter on Wednesday.
After claiming two Scottish Premier League titles in his first two seasons in charge at Celtic Park, while Rangers went trophyless, the spectre of crisis has now drifted from Govan to Parkhead.
With only the league title left to play for, and based on his side's recent performances, Strachan is surely feeling the heat.
In stark contrast, his opposite number at Rangers is enjoying something of a post-Le Guen renaissance, if you'll pardon the irony.
Interview: Rangers boss Walter Smith
The CIS Cup is already in the Ibrox trophy room, the Uefa Cup final is two matches away and the only opposition left in the Scottish Cup for Walter Smith's men to overcome are teams from the Scottish First Division.
For both Glasgow clubs, everything could hang on the outcome of Wednesday night's match.
It's a tough life being in charge of one half of the Old Firm, but pressure can be measured in one of two simple ways; the first being the inability to defeat your rivals in the Glasgow derby.
Kevin Thomson scored the winner for Rangers in the last encounter
Strachan has failed to win a match against Rangers since August 2006 and has not only lost every derby encounter since Smith returned in January last year but his team have also failed to find the net on each occasion.
The second measure of pressure on the man in charge at Celtic or Rangers is determined by their position in the league campaign; second place is simply not an option.
But, to paraprhase the legendary Jock Stein, it's fine to lose every Old Firm derby of the season as long as you win the league title at the end of it.
But a defeat for Strachan's men on Wednesday night would drastically diminish their capacity to narrow the gap on Rangers at the top of the table.
Old Firm clash not title decider - Strachan
And, with it, their hopes of snatching an elusive third league title in a row would almost certainly vanish over the horizon.
Worse still, it could leave their fans facing the prospect of a Rangers title-winning party at Celtic Park on Saturday 26 April, when the teams meet again for their post-split encounter - circumstances the authorities don't want and something the SPL pledged to avoid.
The effect of a Celtic win on Rangers is just as difficult to predict; on one hand, it could be the start of a collapse not unlike the one suffered by Martin O'Neill's side in 2003 when faced with similar circumstances.
But it could just as easily galvanise Smith's men into action when they return to Celtic Park 10 days later for part two of the double-header.
Smith's side are simply not accustomed to losing, having transformed themselves from a beleaguered club humilated by the abject failure of Paul Le Guen's so-called revolution, into an unbeatable force both on the domestic front and in Europe.
It could be argued that the football isn't pretty - but, as the saying goes, it's the winning that counts.
And, let's face it, Celtic have only won two matches from their last eight in all competitions, so they're hardly setting the heather alight themselves.
The same could be said for the quality of play on offer at recent Old Firm encounters.
Long gone is the passion normally associated with the all-important Glasgow derby, only to be replaced by cautious defending and a distinct lack of flair from both sides.
Let's hope the tension and circumstances surrounding Wednesday night's match provides this famous encounter - and the SPL title race - a much-needed shot in the arm.
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