Socceroos midfielder Tom Rogic impressed but was unable to help Celtic as they crashed out of the UEFA Europa League in the round of 32 after going down to a 3-1 home loss to Copenhagen.
Pep Biel and Dame N'Doye struck late to earn Copenhagen a dramatic 3-1 away win over Celtic that completed a 4-2 aggregate victory in the Europa League's round of 32.
Michael Santos, who replaced the injured Mikkel Kaufmann in the first half at Parkhead on Thursday, scored the opening goal in the 51st minute when he was on hand to capitalise on a pair of defensive errors.
Celtic levelled when Ragnar Sigurdsson handled the ball in the box and Odsonne Edouard's Panenka penalty beat goalkeeper Karl-Johan Johnsson, but Biel broke the hosts' hearts.
N'Doye then made sure of Copenhagen's progress to the last 16 by finishing well with two minutes to go, with the draw for the next round set to be made on Friday.
Celtic ended the opening period on top but were unable to break the deadlock, Edouard heading straight at Johnsson from Tom Rogic's clever cross on the stroke of half-time.
The Scottish champions thought they had scored when Callum McGregor steered the ball home, but the goal was disallowed by the referee for a foul by Christopher Jullien on Johnsson.
Moments later, Copenhagen took the lead against the run of play as Jozo Simunovic's awful backpass and Jullien's subsequent slip were punished by the alertness of Santos.
The first leg saw Celtic goalkeeper Fraser Forster keep out Jens Stage's late penalty, which was awarded after a VAR check, but this time the technology went against the Danish side.
Sigurdsson clearly handled a cross into the box, and Edouard kept his cool to convert from 12 yards, seemingly sending the tie to extra time at 2-2.
But Copenhagen had other ideas. Rasmus Falk Jensen set up Biel to slot through Forster's legs, then N'Doye punished more terrible Celtic defending - within six minutes of Edouard's penalty - to complete a stunning raid.