Scorers: Celtic - Scepovic (73), Johansen (79); Astra Giurgiu - Enache (81)
On a night when his team’s performance level was a long way short of the standards to which he aspires, Deila at least had the satisfaction of seeing his players prove themselves resilient enough to dig out a precious victory in spite of a desperate struggle to find any fluency.
Stefan Scepovic’s first goal for Celtic gilded an otherwise less than impressive display by the Serbian striker but crucially set them on their way to three points which keeps them unbeaten at the top of Group D.
If they can repeat this outcome against Astra when the sides face each other again in Romania in a fortnight, Celtic will be well placed to qualify for the knockout phase of the tournament.
On a murky night in Glasgow, a pre-match downpour had left the playing surface slick and amenable to the kind of high-tempo passing football Deila is seeking to deliver at Celtic.
But there was little of it in evidence during a ragged first half during which Astra were unwilling to live up to their billing as the group’s whipping boys.
It might have been far less fraught for Celtic had they claimed an early goal, something Charlie Mulgrew spurned a terrific chance to provide when he tamely sent a free header looping over from Anthony Stokes’ fifth minute corner.
It was as clear an opportunity as the home side would carve out in the opening period, their lack of cohesion soon allowing Astra to take a foothold of their own on the contest. A breakdown in communication between Jason Denayer and Mikael Lustig in the Celtic defence provided the visitors with their first sniff of goal but the Brazilian midfielder William was unable to take advantage.
It provided Astra with encouragement, however, and it was not long before Craig Gordon was once again being called upon to prove his worth on Europa League duty for Celtic.
Outstanding in the two previous Group D games against Salzburg and Dinamo Zagreb, the goalkeeper made his first significant save of this encounter in unorthodox fashion when he kept out Seidu Yahaya’s long- range effort with his chest in the 21st minute.
Gordon reverted to more established means a minute later when he got down to block a shot from Astra captain Constantin Budescu, who had been set up by a sweeping move down the right involving Gabriel Enache and Takayuki Seto after Emilio Izaguirre had been caught in possession.
It was a deeply uncomfortable spell for Celtic, greeted with increasingly anxious groans from the home support, and Astra should have taken the lead when William played in Seto on the left, only for the Japanese midfielder to stab his shot narrowly wide of Gordon’s left-hand post.
Little had been seen in attack to this point of Scepovic, making just his third starting appearance for Celtic, although the £2.3 million striker was hardly being plied with decent service. His first-half chance in the 25th minute resulted in a scuffed shot being deflected wide as Celtic tried to get back on to the front foot.
A raiding run down the right by Lustig succeeded in stretching the Astra defence and their Greek full-back, Vassilis Pliatsikas, came perilously close to putting the ball through his own net as he cut out the cross.
But Celtic continued to appear vulnerable at the other end of the pitch, where Enache should have done better than slide a low shot wide of Gordon’s left-hand post after Mulgrew’s mistake had left the Astra wide man with a premium chance.
Deila’s men at least managed to end the first half giving an impression of being in the ascendancy, Scepovic heading over from a Lustig cross before Stokes saw a shot bravely blocked by Pilatsikas, but it was not enough to spare them from some disgruntled jeers as they left the field for the interval.
Scepovic did nothing to improve the mood of the home fans when he passed up a couple of close-range opportunities to open his Celtic account at the start of the second half. His first miss was perhaps excusable as he headed wide from close range at the back post, having probably anticipated Izaguirre’s cross would be met first by the more central Stefan Johansen.
But there were no mitigating circumstances for his next attempt, a proverbial sitter as he contrived to screw a free header wide from six yards after being picked out by Lustig’s perfect cross from the right.
Deila introduced Aleksandar Tonev in place of the unusually subdued Callum McGregor as he sought fresh energy and invention from his team. The Bulgarian winger was quickly involved, flashing a shot just wide of Astra goalkeeper Silvio Lung’s right-hand post.
While Celtic were now dominating territory and possession, Astra remained threatening on the counter-attack. Cristian Oros might have done better than head over from a Budescu cross, then Enache forced Gordon into action again with a close range effort which the big ’keeper dealt with smartly.
It proved a crucial intervention as Celtic finally made the breakthrough in the 73rd minute. It was sweet salvation for Scepovic, who showed hitherto unseen conviction and finishing prowess as he leapt to power home a fine header from Stokes’ free kick after substitute Mubarak Wakaso had teased a foul from Oros.
Five minutes later, it looked as if the points were secure for Celtic when they doubled their lead. Lung could only weakly parry a low cross-cum-shot by Tonev, leaving Johansen to pounce on the loose ball and drive it into the roof of the net.
But there was to be a nervy finale for the home side after Astra made it 2-1 with nine minutes remaining. It was poor defending by Celtic as William’s cross from the left was flicked home at the near post by the unmarked Enache.