CELTIC have achieved their main objective of reaching the last 32 of the Europa League.

That is worth celebrating.

But the manner in which they crossed the finishing line will have left no one in doubt that they are anything but a force in Europe, nor even a pale imitation of the Hoops side which was playing in the last 16 of the Champions League less than two years ago.

Reality bites, and at Celtic Park last night its teeth were razor sharp. Indeed, the result which was cheered by Celtic's supporters did not come from what unfolded here but over 2,000 miles away on the border of Romania and Bulgaria.

It was there that Astra Giurgiu shocked Dinamo Zagreb by winning their first game of Group D. That 1-0 victory was enough to ensure the Croats can't catch Celtic for second place, even if they beat them in Zagreb next month, a match that is now a dead rubber.

So, the 3-1 loss at Parkhead to Red Bull Salzburg did not damage the Hoops' aspirations of joining the Austrians in next month's draw for the knockout stages.

But, such was the manner of the defeat, it must surely have dented their confidence for what lies ahead when the competition is markedly improved by the arrival of third-placed sides from the Champions League groups. Celtic will be unseeded for the draw and will have every chance of being paired with one of those parachuting big guns.

It would require a massive improvement on last night's performance to make that first two-legged tie anything other than the end of the line for Ronny Deila's side in Europe this season.

Salzburg look far better equipped to progress, as they proved by becoming the first Austrian club to win on Scottish soil.

But, in fairness to those who had been here before them, they did travel with impressive armoury and pedigree to break that duck, having remained unbeaten in their previous eight away games in the Europa League, collecting some notable scalps - including that of Ajax - along the way.

Red Bull have built up their record with an attacking flair which makes them a team worth watching - and fearing.

No one has outscored them in any of the Europa League groups this season.

With the clinical Alan -whose double fired him one ahead of his captain, Jonatan Soriano, in the competition's scoring table - they have a cutting edge the like of which Celtic simply do not carry, nor face on a week-to-week basis.

It would have been a stiff test for the strongest Celtic side. But Deila was denied this with Jason Denayer sidelined with an ankle knock, Wakaso Mubarak and Mikael Lustig ruled out with sickness and a hamstring injury respectively, while the match sharpness of Kris Commons and James Forrest was deemed sufficient only to earn them a seat on the bench.

The absences disappointed the Celtic fans who turned up hoping to cheer their heroes on to qualification.

But this was mixed with a healthy measure of surprise that Deila had elected to bring Leigh Griffiths in from the cold for his first start since the loss at Inverness on August 23.

With Anthony Stokes supporting from left midfield, Callum McGregor - though still nursing an infected big toe - on the opposite flank, and Stefan Johansen in the hole, Griffiths' job was to provide a mobile point to the attack.

His inclusion was a further slap in the face to Stefan Scepovic, the Serbian striker again left on the bench all night.

With Efe Ambrose drafted in to replace Denayer, the Nigerian was another making a return to the starting XI after dropping out after the defeat to Hamilton on October 5.

They were big calls from the manager, the kind which can enhance or damage a reputation that is still being built.

When Deila's team failed to settle and found themselves two goals behind after just 13 minutes - failing miserably to deal with run-of-the-mill Red Bull attacks - the odds were firmly on the latter.

Sure, there was an element of fortune about Salzburg's opener. Massimo Bruno's shot deflected up into the air off Charlie Mulgrew's leg, allowing Alan enough time to glide in between defence and Craig Gordon before coolly drilling a low shot into the net.

But the midfielder should never have been allowed to advance to the edge of the area to fire in his effort.

Five minutes later, more disorganisation at a corner - a common problem for Celtic in recent weeks - allowed Andre Ramahlo time and space to flick on a header.

Again, Alan reacted first, ghosting in ahead of Ambrose to knock the ball over the line from a couple of yards out.

For a moment it looked even worse for the Hoops when Soriano appeared to make it three from a free-kick.

But keeper Gordon had shown remarkable presence of mind not to go for the shot as he knew the ref had indicated the free-kick was indirect.

Even so early, it looked like game, set and match in terms of Celtic's hopes of getting any kind of positive result on the night. Indeed, just retaining possession, let alone gaining a foothold when faced by such a mountain to climb, would have been appreciated.

So it's to their credit that they picked themselves up from the floor after this quick and painful one-two to strike back before half-time.

Emilio Izaguirre whipped in a low first-time cross which Johansen bravely committed himself to making his own.

His half-volley from 16 yards left Peter Gulacsi clutching at thin air as the ball flew in at his right-hand post.

Despite the much-needed lift this gave Celtic, the elusive equaliser proved beyond them, even with the introduction of subs Forrest, Commons and Aleksander Tonev as Salzburg settled on their lead.

Salzburg's third in injury time from substitute Naby Keita served to emphasise the gulf between the two teams in terms of finishing.

Griffiths had given hope of an equaliser prior to the late goal. He sent a shot curling wide and had a point-blank header saved by Gulacsi.

But, much like Celtic's performance overall, his misses only added to the relief that at least Astra were on the money when it mattered.