Those Rangers fans travelling to northern Spain next week might be tempted to make another provisional booking in whichever hotel they lay their hats.

Frankly, having come through this monumental test of character, you wouldn’t bet against Barry Ferguson’s side returning to Bilbao when the Europa League final is staged there on May 21.

Where do you even begin to rationalise the wild oscillations in form we’ve seen from this side across the course of this season?

What a stern examination this proved to be for Ferguson’s players. As if facing the fourth-best side in Spain wasn’t a tough enough task, they were forced to play for 77 minutes a man light after the dismissal of Robin Propper.

The Dutchman’s brainless foul on Inaki Williams was deservedly punished with a red card after he initially escaped with a yellow.

Goalkeeper Liam Kelly saves Alex Berenguer’s penalty to earn Rangers a goalless draw at Ibrox

Kelly celebrates with his team-mates in the first leg of their Europa League quarter-final

Robin Propper’s challenge on Inaki Williams after just 13 minutes earned him a red card

Rangers might well have folded in the minutes that followed. Commendably, their 10 men stuck to the task.

As they finally left the arena, their bodies unable to give any more, they’d been further depleted by Dujon Sterling’s departure. Having committed all of their substitutes, they finished with nine men.

On a night when Ferguson didn’t have a failure in his side, the hero of the hour was Liam Kelly. Selected ahead of Jack Butland, the Scot saved a penalty late on to ensure Rangers remain very much in contention.

This was another striking example of the heights these players can scale when everything is on point.

Unrecognisable again from the rabble which meekly lost at home to the Easter Road side last weekend, they left nothing out there to secure a prized first-leg draw.

Ferguson’s players were everything he hoped they’d be after a lengthy heart-to-heart on Monday. Brave and fully committed in everything they did, they refused to buckle even when the pressure from Bilbao threatened to overwhelm them. What a way for a sixth successive home defeat to be avoided.

Having seen the place empty with 20 minutes remaining at the weekend, Ferguson’s players were fully entitled to bask in the cheers which rained down from every supporter in every stand at time-up here.

The former skipper had spoken in the build-up of how the feeble nature of some of the side’s recent displays had hurt him.

His estimation that the Basques were ‘a step up again’ from Fenerbahce was on the money. They were slicker than the Turks, faster and more physical. Yet Rangers just found something to hang in there.

No one present will need telling that the Scots will need another extraordinary effort to make the semi-final. Bilbao’s only home defeat in La Liga this season came against Atletico Madrid back in August. They’ve not lost any of their five European matches at the San Mames Stadium.

Yet Rangers will now travel as much in hope as expectation.

Rarely has a line-up evoked so much speculation. After the dismal defeat to Hibs, Ferguson had promised changes and he was true to his word. Kelly’s inclusion was the headline news although the selection of Bailey Rice for his first European start was another big call by the manager. The 18-year-old acquitted himself well in trying circumstances before being stretchered off just after the hour mark.

Ferguson’s assessment of Bilbao as a British-style team was entirely accurate. For all the enterprise offered on the wings by the Williams brothers, Inaki and Nico, they were also no strangers to a long ball up to Maroan Sannadi.

The contest was open in the moments before Propper took the long walk.

Vaclav Cerny fashioned the first chance, drifting in off the right flank and firing narrowly wide with a floater. But optimism among the home fans was to be short lived.

In a flash, Nico Williams cutely played in Sannadi. Propper made up the ground and blocked the initial effort then breathed a sigh of relief as the striker’s follow-up went inches wide of the far post.

The Dutchman’s next involvement was a disaster. Oblivious to the fact he didn’t have to commit to a challenge on Inaki Williams, his tackle on the edge of the box was dangerous.

Romanian referee Istvan Kovacs flashed a yellow card but was persuaded to have another look at the incident by VAR Catalin Popa. Propper pleaded his innocence then slowly trudged off the park. An already difficult task suddenly got a whole lot harder.

Trying to create something out of nothing, Ianis Hagi was felled by Ruiz de Galarreta. The Spaniard deservedly picked up a yellow card but not before Ferguson was cautioned for being overzealous in his appeal.

Rangers now needed all the luck they could get. The first slice arrived when Sannadi clipped the outside of the upright.

Inaki Williams, livelier than his brother, had one fierce strike blocked by Leon Balogun and was immediately thwarted again by Ridvan Yilmaz’s sliding block.

By and large, though, Ferguson would have been pleased with the way his side defended Kelly’s goal.

Chances for those in blue were hard to come by. Cyriel Dessers might feel he should at least have hit the target with a shot on the turn after Rice’s intelligent header had kept an attack alive.

Kelly certainly earned his crust in the closing moments of the first period. Having tipped Sannadi’s rising shot over the top, he produced a fine diving save to his left to prevent Oihan Sancet’s header from beating him.

The pressure from Bilbao only intensified after the break. Kelly knew nothing about Sannadi’s flashing strike from Oscar de Marcos’ whipped cross.

Thankfully for the keeper, the ball went inches wide when it looked easier to score.

Connor Barron replaced the stricken Rice after the teenager’s big night ended in the awful sight of him being carted off by stretcher bearers.

With 76 minutes on the clock, Rangers’ resistance looked like it had finally been broken.

Alex Berenguer brought down a long ball to play in fellow sub Gorka Guruzeta, His effort was saved by Kelly only for Berenguer to sweep home the rebound.

The intervention of VAR brought joy then despair for the home fans. The goal was ruled out for offside. But having spotted an earlier handball by Sterling, the officials then awarded a penalty.

Amid extraordinary tension, Kelly held his nerve, leaving a leg outstretched as he dived to his right to ensure Berenguer’s spot kick up the middle ended up in the stand.

This was not Berenguer’s night. Having believed he’d found the top corner with a curler, Balogun stretched his neck and sent the ball for a corner.

With Sterling hobbling off, Rangers had to see out 12 added on minutes with nine men.

Somehow they got over the line. They’ll travel to Spain with the odds stacked against them yet still very much in this tie.