Knowing that Bayern’s sights would be set on a potential treble after already sealing the top-flight title, Mainz set out to take advantage – and they didn’t have to wait long.
Kaishu Sano revived their attack with a brilliant touch on the right side of the box, before sending it back into the middle for Dominik Kohr to fire a bouncing volley into the net.
The visitors remained all over the place in the aftermath, allowing shots from Sheraldo Becker and Nadiem Amiri to make it through and force fine saves from Jonas Urbig.
Vincent Kompany might have been regretting leaving some of his biggest stars on the bench, and saw his side’s chances of equalling the all-time record Bundesliga points tally evaporate further as Mainz got their second.
Sano did some great work in the centre of the park before releasing Amiri, whose shot was parried by Urbig, only for Paul Nebel to arrive and power into the roof of the net.
And a similar situation gave a rampant Mainz a three-goal buffer before the break, with Amiri’s piledriver pushed onto the bar by Urbig before it cannoned upwards and spun onto the goalline for Becker to bundle in.
The Bayern boss simply had no choice but to look to his star-studded bench for the second half, and there was an immediate change in their fortunes as a result.
Mainz seemed powerless to stop them as Konrad Laimer’s cross from the right was volleyed past Daniel Batz by Nicolas Jackson, before substitute Michael Olise made the deficit just one by cutting inside and curling a stunning strike into the far top corner.
The Bayern machine continued rolling from there, and parity was restored with Jamal Musiala’s tap-in after the hosts failed to clear Olise’s cross.
There was only likely to be one winner from there, with Bayern ruthlessly securing the three points when Batz parried Musiala’s cross into the path of Harry Kane, who slotted inside the near post.
Mainz will therefore have to wait until next weekend to secure their top-flight status, but they’ll still likely spend an 18th successive season in the Bundesliga.
While they’ll be more worried about their upcoming UEFA Champions League semi-final against Paris Saint-Germain, the victory means Bayern are still in with a chance of equalling the all-time Bundesliga points record.
Flashscore Man of the Match: Michael Olise (Bayern Munich)