Celtic qualified for the knockout stage of the Europa League despite falling to defeat at home to Salzburg.
Salzburg’s win secured the Austrian’s top spot in Group D, with Alan scoring twice in the first-half and Naby Keita adding another late on.
Celtic’s riposte came from Stefan Johansen and they played more assuredly after the break, but they were undone by Salzburg’s initial zeal.
Astra defeat Dynamo Zagreb in Romania to ensure Celtic finished second.
Celtic were immediately swamped. If Ronny Deila had not been so grim-faced and concerned at the alarming lack of resistance amongst his own players, he would have admired Salzburg’s accomplishment.
The visitors were everything the Celtic manager would wish his own side could be: swift of thought and movement, incisive, quick and precise in their passing, and capable of winning the ball back effectively. The home side were overwhelmed.
Salzburg came into the game as the highest scorers in the competition and the effectiveness of their attack was clear.
There was an element of good fortune about the early goal. Massimo Bruno’s shot was deflected in an arc over the Celtic defence, with the ball dropping to Alan inside the area, with the striker prodding a volley into the net.
Martin Hinteregger’s header demanded a sharp save from Craig Gordon, but the visitors could not be contained.
Four minutes after opening the scoring, Alan added a second. He was a lithe, elusive figure up front, and the Celtic defenders were leaden footed in comparison.
When Andre Ramalho headed a corner on, Alan reacted first and converted from close range.
There was almost a third, when the impressive Jonathan Soriano swept in a free-kick, but as Gordon correctly realised the referee had awarded an indirect set piece.
With Salzburg playing a narrow formation, they could command the midfield, but that also left Celtic with hope on the flanks. It took 30 minutes for a foray to become meaningful, but when Emilio Izaguirre hurled in a cross from the left Johansen finished crisply and accurately.
The goal revived the Celtic support and brought renewed purpose to the home side. It was clear why Salzburg have such an impressive European record though, because they were unfazed. They kept their poise but also their sense of adventure, and one counter-attack took just three quick passes to cover the length of the field.
Celtic were more composed after the interval. They lacked a cutting edge, though, which prompted some fans to holler for James Forrest to be brought on. The sense was that if the game was to be rescued, Celtic needed to be more threatening.
There was a reminder, too, of the danger the visitors still carried. A break upfield saw Soriano and Bruno exchange passes, but the former finished weakly from the edge of the area, sending the ball trundling wide.
Salzburg were capable of a casual aplomb, but they could also be unnerved. Celtic came close when Leigh Griffiths saw a header from Izaguirre’s cross saved, but the equaliser wouldn’t come.
Instead, the substitute Keita added a third with a header after a Salzburg counter attack.