The contest looked to have been settled within the opening quarter of an hour thanks to goals from Mario Mandzukic and Bastian Schweinsteiger, but a needless second-half penalty, converted by Adam Szalai, reduced the arrears. Nonetheless, the record champions showed good composure and added to their advantage through Toni Kroos late on, duly maintaining their place at the top of the table.
Considering the difficulty Bayern have had in recent seasons against Mainz, they could barely have wished for a better start. Less than two minutes had elapsed when Mandzukic turned in the opener from from Thomas Müller's cross. The season's fastest goal so far was soon followed by a second, this time Schweinsteiger nodding in Holger Badstuber's centre to give the hosts a deserved early buffer.
Indeed, Jupp Heynckes' side looked a well-oiled unit ahead of Wednesday's UEFA Champions League group-stage opener against Valencia. Marquee signing Javi Martinez was again left out of the side in favour of the on-song Luiz Gustavo, while Xherdan Shaqiri, another summer arrival, took his place on the left with both Franck Ribery and Arjen Robben sidelined through injury.
Cruising by the interval
With the game's hierarchy effectively decided, Mainz boss Thomas Tuchel made early changes in the hope of upsetting the status quo. Colombian international Elkin Soto and Hungarian frontman Szalai were both swapped in, but neither posed the Bavarians' back-line any additional problems prior to the end of the half.
With seven games to play in 18 days over the coming weeks, Bayern attempted to bring the tempo down in the second period but continued to test Mainz goalkeeper Christian Wetklo, once by way of an awkward Shaqiri free-kick and again as Kroos was afforded space to fire goalwards from distance. However, the game's complexion suddenly changed approaching the hour as Dante's rash challenge on Julian Baumgartlinger gave referee Markus Schmidt no option but to point to the spot.
Szalai from the spot
Substitute Szalai made no mistake with a firm penalty into the corner, but other than making things a tad more nervous for the hosts, the direction of traffic remained the same. Mainz were fortunate not concede when Kroos' cross deflected off the unwitting Mandzukic onto the post. Müller and Shaqiri then each blasted into the side netting and the former saw a skewed left-foot finish diverted onto the post.
Javi Martinez was introduced for the final 15 minutes and showed some of the fighting qualities that made Bayern invest a cool 40 million euros in his services, but the most notable substitution of the day came with two minutes remaining. Claudio Pizarro, already the Bundesliga's highest-scoring foreigner ever, took to the Allianz Arena pitch to make his 336th appearance in Germany's top flight, equalling the record for a foreign player previously held by former Bayern midfielder Ze Roberto and former Schalke 04 and Hertha BSC Berlin defender Levan Kobiashvili.
Kroos caps it
The Peruvian soon reminded fans of his evergreen talent with a clever flick through for Javi Martinez, who sent a superb ball sailing over to the far post, where Kroos fired home with an emphatic volley to cap an ultimately solid three points for the league leaders.
Line-ups and statistics
Andy James reporting from Munich