The Hoops suffered a devastating last-gasp 2-1 defeat in Tuesday's dramatic Group G clash at the Nou Camp, having looked set to take a point from the encounter.
"If we play like that in the home game against Barca, and then in the final two games, I don't see why we can't get out of this group. "If we show the same attitude and application, I think we've got a great chance."
Neil Lennon's men took the lead when a Georgios Samaras header went in off the back of Barca's Javier Mascherano. But the home side hit back through Andres Iniesta just before the interval before Jordi Alba grabbed the decisive goal deep into injury time.
Celtic may have returned to Glasgow without the points but took plenty of plaudits for a performance which followed a stunning away win against Spartak Moscow earlier this month.
They sit second in the section on four points, having opened with a goalless draw against Benfica, and Forster has more belief than ever heading into the remaining group games, starting with the visit of Barca on November 7.
Celtic chief executive Peter Lawwell paid tribute to the manager and players, as well as the thousands of Hoops fans who made the trip to Barcelona.
He is now hoping for another exciting tussle when the two sides meet again in the east end of Glasgow early next month.
He told the club's website: "It was a tremendous occasion and one that we were delighted to be involved in.
"The UEFA Champions League is the stage which Celtic strive to compete on, and we have shown this season that we deserve our place alongside Europe's elite clubs."
Source: PA
Source: PA