Anthony Stokes was on target for Celtic in a pre-season friendly at Parkhead but could not prevent them slumping to defeat to Borussia Monchengladbach.
The Irishman came off the bench to pull a goal back but the German visitors were too strong in this outing as the Hoops prepare to resume competitive action against Elfsborg in Champions League qualifying next week.
Celtic boss Neil Lennon handed a number of youngsters a chance against the Foals, with Darnel Fisher, Calum Waters, John Herron and Callum McGregor all included in the starting line-up.
Charlie Mulgrew, Joe Ledley and Adam Matthews - who have all been struggling with injury - were named on the bench.
Fisher came to the rescue early on when Lukas Rupp powered his way into the box only to see his shot cleared off the line by the defender.
Amin Younes was looking dangerous for the visitors and he cut inside from the left but screwed his effort across the face of goal and past the upright.
Monchengladbach had the best of the possession and the best chances in the first half and so it was no real surprise to see them take the lead eight minutes before the break when Granit Xhaka lashed home from 20 yards.
Scott Brown, Efe Ambrose and Kris Commons were withdrawn at the break to be replaced by Mulgrew, Stokes and Dylan McGeouch.
Amido Balde had been largely ineffective but had a chance with a decent effort that was deflected just wide of target.
Visiting goalkeeper Marc Andre ter Stegen was then booked for a challenge on Tony Watt, before Stokes hit the side-netting with the resultant free-kick.
Matthews and Ledley were both thrown into the action but it was the Germans who extended their lead after 66 minutes when Branimir Hrgota netted after just three minutes on the field.
Stokes managed to pull a goal back for the Hoops after 74 minutes when he sent a lovely free-kick into the net after Ledley had been felled on the edge of the box.