The hosts, meanwhile, have moved five points clear of the relegation zone after an impressive unbeaten run of six matches.
Having lost their first six matches of the campaign before picking up only six points from their first 13 games, few would have given Mainz any chance of surviving this season.
However, since appointing Bo Svensson as manager in early January, the 41-year-old has guided his side to a remarkable run of 25 points from 16 matches.
Extrapolated across the season, that points-per-game rate would currently have Die Nullfunfer in a Europa League qualifying position in sixth place, which shows their astonishing improvement under the man who spent seven years at the club as a player between 2007 and 2014.
Mainz secured their fourth win in five matches with a nervy 1-0 win at relegation rivals Werder Bremen on Wednesday, with Adam Szalai scoring the only goal of a cagey affair after 16 minutes.
The visitors certainly rode their luck on occasions, particularly when Joshua Sargent's equaliser moments before half time was ruled out after VAR adjudged Kevin Mohwald to have fouled Mainz goalkeeper Robin Zentner in the build-up.
Bremen, who were condemned to their sixth successive defeat and look in perilous danger of relegation, had 20 shots and 65% possession across the 90 minutes, but could not find a legitimate goal.
Svensson will be fully aware that a much better performance will almost certainly be required to avoid defeat to Bayern, who will be fully motivated in their hunt for another Bundesliga title.
Equally, though, his side have put themselves in a position where one or two defeats before the end of the campaign would be unlikely to prove fatal, given that Hertha Berlin and FC Koln find themselves five points behind them in the table.
Despite going through a tumultuous week, which saw the club's Champions League defence end at the quarter-final stage to Paris Saint-Germain on away goals as well as Hansi Flick confirming that he will be leaving the club at the end of the season, Bayern took a huge step towards retaining the Bundesliga title by beating Bayer Leverkusen 2-0 on Tuesday.
RB Leipzig's earlier surprise defeat to FC Koln meant that victory would move Bayern 10 points clear of Julian Nagelsmann's side with only four matches remaining, and the Bavarians carried out their task with minimal fuss.
Eric Maxim Choupo-Moting, standing in for the injured Robert Lewandowski once again, scored for the third successive match after only seven minutes, before Joshua Kimmich doubled his side's lead six minutes later after Leverkusen failed to clear their defensive lines.
Regardless of how Leipzig fare against Stuttgart on Sunday, Bayern will be crowned German champions for a ninth successive season should they defeat Mainz.
They are unlikely to find matters easy, though, against a side which has performed a minor miracle to escape the relegation zone, but cannot rest easy in terms of survival yet.
Svensson may bring Jonathan Burkhardt back into the side for his added workrate and ability to drop deep, with Karim Onisiwo potentially making way, but otherwise it is likely to be an unchanged XI from the side which narrowly dispatched Bremen in midweek.
Lewandowski returned to full training during the week and may even return to Bayern's starting XI, with the Poland striker desperate to break Gerd Muller's record of 40 goals in a Bundesliga season.
The 33-year-old requires six goals from Bayern's final four games to break Muller's long-standing record set in the 1971-72 season, which looks a tall order for a player returning from a month out due to a knee injury.
Only a fool would write a goalscorer of his calibre off, though; after all, he is averaging very close to 1.50 goals per game in the league this season.
However, Bayern have no fixture next week due to the DFB-Pokal semi-final's taking place, so Lewandowski may be eased into things from the bench once the match has potentially opened up, particularly given Choupo-Moting's excellent form.
Niklas Sule and Serge Gnabry will also hope to be involved having appeared to recover from a thigh issue and COVID-19 respectively, but likewise Flick may see no reason to rush the pair back into things.
Mainz 05 possible starting lineup:
Zentner; St Juste, Bell, Niakhate; Brosinski, Barreiro, Kohr, Boetius, Mwene; Szalai, Burkhardt
Bayern Munich possible starting lineup:
Neuer; Pavard, Boateng, Hernandez, Davies; Kimmich, Goretzka; Coman, Muller, Musiala; Choupo-Moting
We say: Mainz 05 1-3 Bayern Munich
Despite Mainz's brilliant form of late, we expect Bayern to wrap up a ninth consecutive Bundesliga title in style.
Svensson's side were actually quite underwhelming against Bremen despite gaining a crucial win, with Bayern's deeper squad likely to pay dividends during a congested schedule.
Whether Lewandowski starts or not, it would be little surprise to see the Poland hitman get himself on the scoresheet at least once as he looks to chase down Muller's record.
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