City face a huge task to reach the knockout stage for the first time after slumping to the bottom of Group D with a disappointing 3-1 defeat to Ajax in Amsterdam. Roberto Mancini says his side now need a "miracle" to progress from a group that also includes Real Madrid and Borussia Dortmund, and Barry concedes chances are slim. But the England international is refusing to give up hope completely.
"The way the results have gone has made it tough but we have to try to win all three games and that would give us an outside chance," he said.
"We would have 10 points, and that is all we can do - it's a massive, massive task, but it is still there and we have to try to do it.
"Dortmund winning is the worst possible result. When you are beaten you are looking for a bit of help from elsewhere and it didn't come.
"But we have to concentrate on ourselves rather than looking at other teams.
"There is an outside chance and if they are behind us all the way it will make it easier for us.
"It's not over yet. You can't just roll over when there are points available and we will give it our all to try to win all three games."
City's challenge resumes when they host Ajax in a fortnight. That is followed by Real Madrid's visit to the Etihad Stadium and then the trip to Dortmund in December. The Premier League champions have just one point from their first three games after surrendering a lead given to them by a fine Samir Nasri strike. Yet even that 22nd-minute effort came much against the run of play and Ajax levelled on the stroke of half-time through Siem de Jong. A Niklas Moisander header and a deflected Christian Eriksen strike secured victory for the Dutchmen after the break. Barry, 31, said:
"They dominated possession in the first half, and we caught them on the counter-attack. From that we should really build.
"We had a chance to maybe go 2-0 up and didn't take it, and then they scored at a great time for themselves just before the break.
"We started the second half well but they then scored from a set-piece and that deflated us.
"Overall we can't complain as we were beaten by a team that dominated the game.
"We didn't go out to start slowly, it's just the way he game went.
"They played in the style they have played for many years, by keeping the ball. We are not sure at the moment what the problem was.
"From the outside people saw it as a great chance to win, and then get back-to-back wins to set us nicely for the last two games. It didn't work out like that and we have an uphill task now.
"If we can get ten points we will snap their hands off now. If it's not enough we will be disappointed again but there are three games and we need to win all three."
Barry also urged disappointed fans to stick with the team in the remaining games. He said:
"If we have let them down in any way, we are sorry but we have two home games and one away and we need their support."