Bayern coach Niko Kovac handed first starts to Philippe Coutinho and Ivan Perisic, but it was their substitutes, Thomas Müller and Davies, who combined for the final goal in the 81st minute when Müller gave the Canadian teenager a tap-in.
Robert Lewandowski also scored to take his tally to six goals in three Bundesliga games this season, with Benjamin Pavard, David Alaba, Perisic and Kingsley Coman grabbing the other goals after Jean-Paul Boetius’ early opener for Mainz.
Coutinho played just behind Lewandowski and was involved early as he won the ball to set up the Poland striker for the game’s first big chance in the fourth minute.
But Boetius stunned home fans in the sixth minute, when Pavard left him free to head Ronael Pierre-Gabriel’s cross past the static Manuel Neuer in the Bayern goal.
Bayern seemed out of sorts as the number of missed passes increased, partly due to the visitors’ aggressive pressing. But the home side gradually gained the upper hand and Pavard equalized off Perisic’s cross in the 36th.
Alaba made it 2-1 with a brilliant free kick just before the break, and there was no stopping the home side after that.
Also Saturday, Hertha Berlin conceded two own-goals in a 3-0 defeat at Schalke and Cologne rallied from a goal down to win 2-1 in Freiburg for its first victory back in the top flight. Paderborn drew at Wolfsburg 1-1, and Hoffenheim held Bayer Leverkusen 0-0.
Union Berlin hosted Borussia Dortmund later for its second home game in the Bundesliga.
Source: FOX Sport