Celtic manager Neil Lennon has declared that he was disappointed with his side's lack of composure to see out Champions League qualification against Benfica.
A Georgios Samaras header had Celtic in a position to guarantee a place in the last 16 at the break before things unravelled in the second half.
Benfica clinched victory with a clinical volley from Ezequiel Garay 20 minutes from time.
Lennon admitted that his young side buckled under pressure at the Stadium of Light.
He told reporters: "I'm disappointed with the two goals we conceded. There was a lack of composure, a nervousness, about us at times on the ball.
"It is a young team and this is a difficult place to come and play football. We gave it away in bad areas and cheaply and pressure is inevitably going to come from those errors."
Celtic only need to match Benfica's result in the final group match at home to Spartak Moscow to reach the knockout stages.
