UEFA Europa League winner Frankfurt seemed a tricky first opponent for the German champion, but Julian Nagelsmann's side swept them aside in sensational style.
Having defeated RB Leipzig 5-3 in the DFL-Supercup last week in its first competitive match since Robert Lewandowski's departure, Bayern was 5-0 up by half-time on Saturday (AEST), Joshua Kimmich, Benjamin Pavard, Jamal Musiala and Serge Gnabry joining Mane on the scoresheet.
Manuel Neuer's sloppiness gifted Randal Kolo Muani a consolation, yet it was a minor blip in a supreme Bayern display, and Musiala capped things off with his second late on.
Bayern had full control by the 10th minute. Kimmich fooled Kevin Trapp with a long-range free-kick that clipped in off the right-hand upright, before Pavard lashed in his second goal in as many games.
Juventus-linked Filip Kostic teed up a golden chance for Frankfurt to drag itself back into contention, only for Tuta to head against the woodwork, which then denied Bayern a third after Gnabry's poor pass sold Thomas Muller short in front of goal.
Another glorious Eintracht chance went begging due to Jesper Lindstrom's profligacy, but Bayern had its third after Trapp had parried Musiala's effort onto the crossbar, Mane stooping low to head in Gnabry's cross.
Mane turned architect for Bayern's fourth six minutes later, drawing out the Frankfurt defence and finding Muller, who squared for Musiala, and it was five before half-time when Gnabry squeezed home.
Kristijan Jakic, one of three half-time Frankfurt substitutes, thought he had pulled a goal back in the 56th minute, yet it was disallowed for offside.
Neuer hardly covered himself in glory in that incident, and Bayern's captain was entirely at fault eight minutes later when he was bundled off the ball and humiliated by Kolo Muani.
Musiala had the final say, though, tucking in after Leroy Sane's exquisite pass to add further gloss to a statement win.
Bayern hosts Wolfsburg in their second Bundesliga game of the season, while Frankfurt will travel to Helsinki for the small matter of facing UEFA Champions League winner Real Madrid in the Super Cup.