AS OLD Firm defeats go, Rangers’ first-half collapse at Parkhead last night was right up there as one of the most shambolic displays in some considerable time.

From the moment Kemar Roofe kicked off proceedings, the champions looked startled and were swallowed up by both the occasion and raucous atmosphere.

There appeared to be no clear structure and the game plan devised by the coaching staff and players leading up to the match was declared dead as early as the fourth minute when Reo Hatate opened the scoring.

In these powder keg fixtures it’s vital you don’t concede early if you are the away side but from kick-off, it seemed a Celtic goal was only a matter of time and so it proved.

Yes, the goal shouldn’t have stood given the head knock sustained by Joe Aribo and Calvin Bassey but, if Bobby Madden had ruled the goal out, Celtic would’ve surely scored shortly after given the pressure they were applying.

The Light Blues had to call on Allan McGregor to save their blushes following defensive mistakes before two goals in as many minutes just before the break rendered the match over as a contest.

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The image of Borna Barisic cowered on his haunches as Liel Abada was afforded all the time in the world to slot home will take a long time for supporters to get over.

The Croatian’s abject performance was reminiscent of Fernando Ricksen’s horror show in the 6-2 drubbing back in 2000. On that occasion, Dick Advocaat hooked the Dutchman after 20 minutes, Giovanni van Bronckhorst, who played on that fateful day, should’ve done likewise.

Barisic wasn’t the only player who failed to cope with the occasion, there were several others with only McGregor, Ryan Jack and Leon Balogun able to hold their heads high.

It was a bad night at the office, one that saw Rangers knocked off their perch at the top of the Scottish Premiership table for the first time this season.

However, it’s important to remember the league is not won or lost on last night’s showing.

The Rangers boss knows more than anybody that losing to Celtic doesn’t mean you’ve necessarily lost the league. His first Old Firm encounter as a player saw him on the receiving end of a 5-1 humbling but he would have the last laugh as he helped Advocaat’s team win the treble including the famous title win at Parkhead.

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More recently, Walter Smith’s Rangers side were destroyed 3-0 at Parkhead at a similar stage of the season back in 2011 as Neil Lennon’s men moved eight points clear at the summit.

We all know what happened at the end of that campaign.

Last night’s debacle MUST act as a wake-up call for van Bronckhorst and certain players to get their title bid back on track. The new manager bounce is gone, and he needs a reaction on Sunday against a Hearts side who will fancy their chances of compiling the misery at Ibrox.

This Rangers team have proved in the past that they are capable of bouncing back from adversity and you’d like to think they have the mentality and hunger to do so again.

As much as it was a painful pill to swallow, van Bronckhorst will have learned a lot about his players and who he can rely on going forward. It wouldn’t be a surprise to see wholesale changes to the starting XI when Robbie Neilson’s men come to town.

You also have to factor in the imminent return of Alfredo Morelos, Filip Helander and Aaron Ramsey and suddenly the outlook looks a little rosier.

Getting the Welshman up to speed and involved in a playing sense is paramount to Rangers getting back to winning ways. He is a difference-maker and someone who has the experience, mentality and superstar factor that can drive the champions on to retain the title.

Van Bronckhorst needs buy-in though, there were too many players who looked disinterested at Parkhead. If there is a lack of belief in a manager’s methods, they don’t tend to last long in a job.

February is a pivotal month for the Light Blues, they cannot afford to let last night and the general malaise that’s seeped in following their return from the winter break to manifest itself.

They may have lost the battle, but the war is far from over.