After losing to Benfica in their last game, the SPL club must better the Portuguese club's result in their final group match against Spartak Moscow to qualify for the last 16.
And Ambrose thinks the memory of keeping the likes of Lionel Messi quiet can prove an ideal formula.
He said in the Daily Record: "Messi is a good player and nobody will argue against that but we made things difficult for him and he will never forget playing against a team like Celtic.
"That is the spirit we will be taking to the last game to make sure that we win, although the result from the other game in the Nou Camp will determine our fate.
"But we are going to do our best to ensure we make it through. I strongly believe we are going to make it. We started well and want to finish the good work.
"I know it's going to be tough but we are ready for the challenge. Our last game is back in Scotland against Spartak Moscow and we know what we have to do.
"It was a great achievement to beat Barcelona and I can never forget that game. But we have to look beyond just beating Barca. We want to go far in the competition."