Leverkusen holds top spot in the table heading into the game at its BayArena home, the final outing for both clubs before the mid-season break in Germany.
Peter Bosz's side is unbeaten after the opening 12 league games this season, the first time that has happened for the club since the 2009-2010 campaign. However, Bayern has won three of its past four games in Leverkusen, including a 4-2 triumph there in June.
On the eve of the much-anticipated clash, Flick outlined the challenges his team will face on the road, though also made clear the size of the task facing Leverkusen – particularly if everyone for Bayern is at "100 per cent" for its final outing in a hugely successful 2020.
"This is a strong team. Leverkusen has had a very, very good run," Flick said.
"It has confidence and is in a good mood. The idea it has is a good one: it plays for possession and is able to put its stamp on the game.
"We need to be good defensively and make sure not to lose the ball. If everyone is 100 per cent there, it will be difficult for Leverkusen to beat us."
Kingsley Coman has certainly been at his peak so far in the campaign, providing a competition-high seven assists in the Bundesliga – already a new personal best for the Frenchman.
The winger has had a hand in at least one goal in each of his previous five Bundesliga games for the first time, leading Flick to praise the player for his recent run of form.
The Bayern boss hopes Douglas Costa, Serge Gnabry and Leroy Sane can raise their standards too, making clear each of the trio has "room for improvement".
Sane's form has come under close scrutiny in particular, the big-money signing from Manchester City having started only five league games so far, though he has contributed three goals and the same number of assists.
Gnabry has found the net four times but is yet to set up a team-mate in 775 league minutes, while Costa has produced one goal and a solitary assist having seen less action than the other trio.
"Kingsley Coman is currently the benchmark for everyone when it comes to scoring contributions," Flick said.
"The other three – Costa, Gnabry and Sane – still have room for improvement. We hope that they will be close to 100 per cent tomorrow. That would help us a lot."
Flick revealed Bayern will not rush back Joshua Kimmich from a knee injury suffered in early November, while Leon Goretzka will be assessed after training to see if he can feature against Leverkusen.