Celtic U19 opened up their NextGen campaign with a defeat to Sporting Lisbon as goals from Iuri Medeiros and Luis Cortez saw the group favourites leave with three points.
The Hoops had taken the lead through striker Denny Johnstone, but a mix of poor defending and quality finishing saw the Portuguese side home.
The home side were opening their NextGen campaign after failing to qualify from a group that included Barcelona, Marseille and Manchester City, but the SPL U19 champions finished above the English side.
Sporting Lisbon already had a win under their belts after defeated Aston Villa to put them top of the section, the Portuguese side were defeated by eventual champions Inter Milan at the quarter final stages last season, after going undefeated in their group.
The visitors were handed a blow within the first ten minutes as centre half Tobias Figueiredo limped off of the field to be replaced by Braima Cande, but the change didn’t affect Sporting as they almost opened the scoring when Farley Rosa curled a free kick over the Celtic wall, but keeper Leonardo Fasan managed to claw the ball away for a corner.
Celtic however against the run of play took the lead, as Patrik Twardzik played Callum McGregor on the left wing; he cut inside and squared the ball to the unmarked Johnstone who fired home from six yards out.
Despite being behind the Portuguese side continued to press forward and had several chances before the break, with Rosa, Carlos Mane and Alexandre Guedes all going close, until deep into injury time Mederiros beat the Celtic offside trap and stroked a ball from Mane into the net from close range.
Sporting were lucky not to be reduced to ten men at the start of the second half after a poor pass across the park allowed Twardzik to nip in and gain control of the ball, but just before he raced into the box he was cruelly brought down by Ruben Semedo, but referee Greg Aitken deemed the foul only merited yellow.
The Scottish side were starting to gain control over the game and nearly took the lead when Lewis Kidd unleashed a powerful strike from long range that Mickael Meira in the Sporting goal done well to get behind and hang onto the ball.
With less than quarter of an hour left the visitors took the lead as substitute Cortez got a hold of the ball 30 yards from goal and unleashed a vicious strike past the helpless Fasan in the Celtic goal to give Sporting the advantage.
Sporting could have extended their lead moments later as Marcus Fraser failed to deal with a cross from the left wing, allowing the ball to arrive at the feet of substitute Cristian Ponde, but his lob over Fasan landed on the roof of the keeper’s net.
Celtic pushed forward in the late stages in hope of an equaliser, but a strike from Twardzik after a free kick from the right landed at the feet of the winger inside the box was to be the Hoops last opportunity, but he could make little of it and the visitors left with all three points.