Old Firm derby highlights contrasting trajectories of Celtic and Rangers

If Old Firm derbies define a Scottish season, it is fitting Sunday’s version sums up the curious nature of the campaign to date.

A Celtic success, the most likely outcome, would all but confirm the reclaiming of the Premiership title. Ange Postecoglou’s team would be nine points and at least 20 goals ahead of Rangers with three matches to play.

Yet an alternative scenario cannot be completely discounted, demonstrated by Rangers’ deserved success over their oldest foes in the Scottish Cup semi-final on 17 April.

Related: Furuhashi’s goal helps Celtic see off Ross County and restore six-point lead

Rangers’ season has been one of epic highs – that Hampden triumph and victory over Borussia Dortmund en route to the Europa League semi-final – but horrible lows. It has been forgotten that the 10 men of Malmö bundled Rangers out of the Champions League at the qualifying phase. On Boxing Day, Rangers held a seemingly unassailable six-point lead at the summit; subsequent stumbles against Aberdeen, Ross County and Dundee United plus a trouncing at Celtic Park collided with Postecoglou’s side finding their sweet spot.

It is unfair to declare Giovanni van Bronckhorst’s appointment as the successor to Steven Gerrard as a mistake. Rangers’ European run, very much alive despite a 1-0 defeat to RB Leipzig on Thursday, is worthy of huge respect. Should Rangers take the ultimate Europa League prize – another possibility it would be unwise to laugh off – domestic failings will barely matter.

For now, given Celtic lie in immediate opposition, it is merely fair to highlight the contrasting fortunes of sides who were separated by 25 points, in Rangers’ favour, when last season concluded.

It may be denied now, but a noisy percentage of the