Euro Reaction Leverkusen Defeat Aberdeen Victory Mentality?

Celtic : The Unrecruited View is a podcast for the fans a view from the Stands.The Sunday view Ryan and Jp chatted about the last two games against Leverkusen and Aberdeen.Thursdays game against the Germans was frustrating not to win but we can take some positive’s from it and learn from them..is it a mentality aspect that we cant get to the next level in Europe?