City have again failed to impress in the competition and have little room for error as they host Bayern Munich in a crunch clash at the Etihad Stadium on Tuesday
Manuel Pellegrini's men have claimed just two points from four games in Group E and will be eliminated if they fail to beat the Germans and there is a winner in the game between CSKA Moscow and Roma.
That would represent a huge disappointment for City, who - after winning a second Barclays Premier League title last season - had begun the campaign with high hopes.
To exit at the group stage for a third time in four attempts would be viewed as regression and midfielder Nasri knows the current team should be doing better.
The Frenchman, 27, told several national newspapers: "Sometimes people say our team is a little bit old, that's what I read.
"A midfield player is in his prime at 27-31, 28-32, so I think it's the perfect age.
"And let's be honest, we need to do something or otherwise next year it is going to be new players.
"That's how we work when you play for a big team, a big club
You have to respond and show everyone you deserve to qualify.
"I think we are really lucky we are two points behind with two games left and have a chance to qualify
We need to take it now because we are not going to have any favours from anyone else any more.
"Let's be honest
With the salary of every player and the level of those players, 90 per cent of the team is world class, then not to qualify from the first round of the Champions League would be a huge blow for the club - and for us as well.
"With the players we have, the owner gives us his trust, we have to return it in the Champions League."
Scenarios do exist where City could still progress if they only manage a draw against Bayern but much would depend on other results.
Only with a victory can they be sure of maintaining interest and defender Martin Demichelis has promised they will fight hard in hope of achieving it.
The Argentina international said: "We are not happy with the performances we have put in in the Champions League
We have a good squad and should do much better.
"But there are two games left and I am sure we will play better
Why shouldn't we dream of going through to the last 16?
"From the start it is a question of being straight at it and putting in the best performance we can, looking to control the game and play with aggression."
But Demichelis, who spent nine years at Bayern earlier in his career, is well aware the task will not be easy
Bayern are already through to the knockout stages and have several injuries but Demichelis claims that will not affect their attitude towards the game.
The 33-year-old said: "My experience of playing over there tells me it won't be easy
Maybe they won't field their strongest starting XI but they have the quality of players in the squad and on the bench."
Source: PA