Barca need to win after suffering an opening-day defeat in the group stage of the competition in Monaco.
In his pre-game press conference, Flick was asked whether his past at the German powerhouse would be a factor in the game, reports Xinhua.
"The past has no value; what matters is here and now and now we can't have any influence over what happened in the past," replied Flick. "What we can influence is tomorrow's game and we want to win that," he continued.
Flick said Barca and Bayern were "two similar teams (...) I played there (Bayern), I coached them. It is an excellent club and I know a lot of people and have a good relationship with players and directors, but this is a new chapter in my life."
"I feel very good here (in Barcelona) and I feel the fans are behind us. It's a nice feeling and it makes me want to do everything for them," he added.
"Bayern are an excellent team and everyone wants to try and play against the best," explained the Barcelona coach, who believes that so far things had gone well at Barcelona because they had "focused on one game at a time."
Barcelona travel to play Real Madrid at the weekend, but all Flick would say was that "every game has its demands and they are all prepared differently," although he admitted the 'Clasico' at the weekend "would be difficult," because we don't have much time to prepare."
In La Liga, Barca are at the top of the standings with 27 points from 10 games with archrivals Real Madrid following close behind at 24.