This 2-1 defeat in Lisbon means that the Portuguese club join Neil Lennon's side on seven points but now sit in second place in Group G by virtue of a better head-to-head record.
All this means that, in their home game against Spartak Moscow on December 5, Celtic must better the result Benfica achieve in Barcelona to progress to the last 16 along with the La Liga side, who have won the group. If Celtic and Benfica remain tied on points, it will be the Portuguese who progress after goals from Ola John and Ezequiel Garay gave them the win they needed to keep alive their hopes of progressing.
Georgios Samaras, so often a hero in Europe for Celtic, equalised just before half-time but, on this occasion, it was not enough. And so it goes to the final game, but before a ball was kicked in Lisbon last night, at least Lennon had been able to tell his players the welcome news that, no matter the outcome in the Estadio da Luz, their flame would still be burning in Europe after Christmas, courtesy of Barcelona's 3-0 triumph over Spartak Moscow earlier in the evening.
Several hours prior to that, in the Estadio Nacional, Lennon and his players surveyed the scene of the club's proudest moment 45 years ago. The manager chose the surroundings to reiterate his belief that the current crop of Celtic players could join Barcelona in the last-16 draw on December 20.
Lennon's subsequent line-up was as robust as it was predictable, given that Scott Brown, Joe Ledley and Gary Hooper were always assured of their places if they could prove they had overcome the injuries which had threatened their participation. It again confirmed that, despite slurs over negativity, the manager has subscribed to the theory that maximising the threat you carry in attack can provide vital options should the need arise, as it did last night.
Having opened the scoring in all four of their away games in Europe this season, even at Camp Nou, and having succeeded in winning all but that one against Barcelona, Lennon's advocacy of asking questions of the opposition is a tried and trusted formula.
This time, amid the dreich, swirling rain and colourful flags, they were the ones having to come up with the answers as Benfica took the lead after only seven minutes of tentative play. Eduardo Salvio outmanoeuvred Adam Matthews on Celtic's left and, from the goal-line, sent in a low cross which Brown attempted to clear as Oscar Cardozo tried to shoot. The ball broke back to where John was lurking, and he clinically dispatched a shot beyond Fraser Forster.
The pace and guile in the wide areas, augmented by the power of Cardozo in the centre, ensured Celtic's defenders were going to have every bit as tough a shift as they had been required to put in against Barcelona.
Determined not to yield any more advantage, Celtic increased the physicality, and the local fans joined the home team players in becoming incensed when, in quick succession, Brown got involved when the ball was dead with Andre Almeida, then Victor Wanyama was accused of deliberately elbowing Enzo Perez, who had to go off to stem the flow of blood from his lip. Wanyama did end up in the book, though – a late caution ruling him out of the Spartak tie.
The entire Benfica camp were spitting blood a few minutes later, though, when Celtic exposed their weakness at cross balls to equalise. Once again, it was the combination of Charlie Mulgrew's pinpoint delivery to the back post, totally misread by goalkeeper Artur, and Samaras' perfect positioning which allowed the Greek striker the simplest of chances, heading down into the unguarded net.
As the heavens opened and the game became more open, errors and half chances became more frequent, and, after his initial slip on the half-way line, Kelvin Wilson had to be at his best to block a Nemanja Matic shot. Forster used his right foot to prevent John regaining the lead for Benfica two minutes before the break after yet another piercing break down Celtic's left. That was the home side's 17th attempt on goal, but the vast majority of these were desperate, reflecting their need for victory.
The change at the interval, Biram Kayal for Mulgrew, was enforced, and the Israeli internationalist was a useful recruit to the rearguard action being mounted.
Lima did find a way through after tricking Ambrose on Benfica's left, and his shot was good enough to beat Forster, but not Matthews, who had slipped in behind his goalkeeper to be in place to clear.
Kris Commons replaced Brown and he soon made an impact – his free kick finding the head of Mikael Lustig – but the effort was blocked en route to goal. Garay had no such difficulty finding the net with his winning volley seven minutes later, however.
Tony Watt was thrown on for Ledley to try and conjure up another big finish for Celtic. He did have a chance in injury time, but the effort flew wide. That big finish will now have to wait until the Russians come to Glasgow.