The Premier League champions find themselves on the bottom of the Group D table with just one points from three matches but Barry feels that qualification to the next stage is still achievable starting with a home win over Ajax tomorrow night.
"The manager, after the Ajax game, when everyone was disappointed, still instilled us with belief that if we win the (last) three games, then we can go through," said Barry.
"As players we believe in that too. While it is still possible to qualify - that is our aim - starting tomorrow night against Ajax, we are going to try for three points and go from there."
He added: "It is quite clear that we have not produced our best performances against the quality of opposition that are in the Champions League and, when it comes to these games, when you're not producing your best you get found out. That seems to be what has happened."