CELTIC'S victory over Barcelona a fortnight ago sent shockwaves around the world.

A corner of Lisbon felt the tremors more than most. The result not only bolstered Celtic's chances of reaching the Champions League knockout phase but also reduced Benfica's chances of doing likewise. The general assumption when Group G was drawn was that Barcelona would sweep all before them leaving the other three – Spartak Moscow make up the quartet – to battle it out for the second qualifying spot. The Catalans will almost certainly still finish in first place but it is Celtic, rather than second seeds Benfica, who are now in pole position to progress behind them after that stunning victory over Barcelona in Glasgow.

It has left furrowed brows in sections of the Portuguese capital. Benfica, European Cup winners in 1961 and 1962 and finalists a further five times, are a club accustomed to reaching the latter stages of major tournaments on a regular basis. Last season they reached the quarter-finals of the Champions League before being beaten by eventual winners Chelsea; they reached the Europa League semi-final the year before, and the quarter-final of the same competition the season before that.

They may no longer be a club considered to be a part of the European elite but there is no doubting both their pedigree or their resourcefulness. They sold two of their best players – Javi Garcia and Axel Witsel – in the summer for a combined fee of around £50m, and have barely suffered as a result. They are undefeated in the Primeira Liga, tucked in just behind leaders Porto on goal difference after nine games, and on Friday night progressed comfortably to the third round of the Portuguese Cup. Lima, the Brazilian striker signed from rivals Braga for around £4m, has carried on where he left off last season with eight goals to his credit already.

Only in the Champions League have they not had things their own way. An opening night draw in Glasgow was thought at the time to be a useful point, while defeats at home to Barcelona and away in Moscow were not ideal but not entirely unexpected. A subsequent home win over the Russians got them back on track but Celtic's win over Barcelona on the same night has left Benfica in something of a hole. Tonight's game against Celtic in the Stadium of Light has, therefore, taken on extra significance.

Victory is imperative for Jorge Jesus' side. Should Celtic secure a score draw, and Barcelona win in Moscow in the group's other game, then Neil Lennon's will go through to the last 16 with a game to spare. Even a win may not be enough for Benfica given their final group game on December 5 takes place at Camp Nou when Celtic will be entertaining Spartak, but the various final-day permutations will all be redundant if Benfica do not first secure a win this evening.

"Celtic will be really motivated after that victory over Barcelona," said Jose Moreira, the former Benfica goalkeeper latterly on the books of Swansea City. "But I think Benfica, both as a team and individually, will be able to beat Celtic and take a step towards the knockout round of the Champions League."

Benfica's prospects will be boosted by the return of Luisao. In what surely must go down as one of the most bizarre incidents in European football this season, their captain and defensive stalwart was suspended by FIFA for two months for knocking over a referee during a friendly. He returned on Friday for the cup tie against Moreirenese and is likely to keep his place for what is Benfica's biggest game of the season so far.

"I had hoped Luisao would have had a more difficult game on his return but Moreirense opted for a direct game and he is very strong in dealing with that," said his manager. "It was good for him to play 90 minutes and there was no sign of tiredness towards the end."

"We all know the importance of Luisao," added Moreira, without a club after being released by Swansea last season. "He is the team captain and I think it will be a great boost to have him back for the game with Celtic, a match that will be decisive. He has been there for many years, understands the mystique of Benfica, and knows the club inside and out. On the field he is a leader and all his experience will be crucial."