Bayern routed Barcelona in the 2019-20 UEFA Champions League quarter-finals in a one-off match in Lisbon.
The Catalans have seen many changes in personnel since then, with none larger than Lionel Messi leaving for Paris Saint-Germain.
“We are talking about a recent event with current squad members involved,” Koeman said.
“Now we have the chance to turn that result around. We have to be strong, look for a high tempo game and show off our style.
“We have great players with a lot of technical ability who can cause Bayern problems.”
Barcelona have claimed seven points from three games in LaLiga following Messi’s departure, while Antoine Griezmann joined him out the exit door with a deadline day move to Atletico Madrid.
“We have had changes in the squad and we need time,” Koeman said.
“But in football there is not much time and the game against Bayern is an interesting one from which we can draw some conclusions about where we are.”
Bayern boss Julian Nagelsmann paid respect to Barca, insisting they remained strong despite their absentees.
“They’ve no longer got someone as extravagant as Messi, but they have other players who can make a difference,” he said.
“We are prepared for everything. I’m not of the opinion that they are a lot worse off now. In any case, we definitely want three points.”