One of the highlights of last season for Neil Lennon's side was beating Barcelona as the club celebrated its 125th anniversary.
And Ambrose has insisted that there is no reason to believe that Lennon's men cannot do the same again.
He said: "I believe we can still beat Barcelona and create the same history again.
"It will be difficult because after losing our first game the pressure is on us because we have to win to keep ourselves in the group.
"Barcelona are the best in the world and the fact we beat them here last year is going to make it even harder for us.
"The most important thing is for us to believe we can do it again. Nothing is impossible in football."
Meanwhile, the defender has started to establish a central defensive partnership with Virgil van Dijk, a pairing that looks as though it could last the season since Steen Mouyokolo is out with a ruptured achilles.
He said: "I think it's a good partnership. We understand each other, and the most important thing is we both speak English.That helped a lot."