Published Tuesday, 20 November 2012
Samras scored for Celtic. (© PA)
A score draw would have been enough for the Scottish champions after Barcelona beat Spartak Moscow 3-0 in Tuesday night's other Group G fixture.
The game at Estadio da Luz in Lisbon was level at half time.
Benfica had opened the scoring after seven minutes with a strike from Ola John, before the Hoops equalised with a Georgios Samaras header on 32 minutes.
Celtic came under siege in the second period and it seemed another goal was coming for Portuguese hosts.
Centre back Ezequiel Garay scored on 71 minutes to nudge Benfica ahead again.
Lennon's men pushed for the equaliser but were unable to find one.
"I'm disappointed with the two goals we conceded," the Lurgan-born manager told Sky Sports after the game.
"There was a lack of composure at times and a nervousness on the ball. I didn't feel a goal was coming but we were under pressure.
"This is a hard place to come and play football especially under the circumstances."
However all hope is not lost, as the team can still progress to the last 16 when they host Spartak Moscow in Glasgow for the final group game - while Benfica face Barca.
Lennon continued: "We have one more crack at it and we know what we have to do - beat Spartak Moscow at home."