The experienced coach has stressed that they will not underestimate the Nullfunfer, and he has little doubt that the league leaders will bag the full three points
The Bavarians were beaten 3-2 in last season's away game versus Thomas Tuchel's men, and Heynckes has warned his team to remain focused.
"I've studied Mainz very closely and know exactly how they play, the runs they make, where they press and also how to combat that. My players know exactly what they have to do," Heynckes said at a press conference.
"It's never easy against Mainz. The team has a good structure and good tactics. And Bayern have made very heavy weather of it against Mainz in recent years.
"But despite that, we have to be capable of seeing off even a team as cleverly assembled as this. We have to keep on winning."
Saturday's encounter is scheduled to kick off at 15:30CET.