Bayern rode their luck until finally breaking the 05ers' resolve through Bastian Schweinsteiger and Mario Götze, but success elsewhere for Borussia Dortmund and FC Schalke 04 means the race for honours, mathematically at least, carries over into next week.
The champions in waiting started brightly as Dutch winger Arjen Robben and roaming left-back David Alaba stung the palms of Loris Karius either side of a promising Mainz breakaway involving Ja-Cheol Koo. Nicolai Müller was next to try his luck for the stout-hearted hosts, but he could only find the gloves of Germany no.1 Manuel Neuer.
Curiously enough, Mainz were the last side in the Bundesliga to stop the Bavarians from scoring back in April 2012 and, those aforementioned efforts aside, were doing another fine job at keeping clear-cut chances to a minimum. The gaps were opening up at the other end, meanwhile, as Neuer, on one such occasion, had to rush out of his box to deny Shinji Okazaki.
Perhaps it was the scarcely employed defensive pairing of Martinez and Jerome Boateng, but Bayern looked a shadow of their unbeaten selves for much of the first half, with Okazaki striking the post, only for the linesman's flag to go up somewhat belatedly for offside.
The woodwork came to Bayern's rescue yet again early in the second half, this time keeping out Eric Maxim Choupo-Moting's ferocious 10-yard drive, before leading Bundesliga scorer Mario Mandzukic and Robben brought a pair of rare, and fine, saves out of Karius at the other end.
Bayern come good
Unhappy with his side's inability to unlock the Mainz door, Pep Guardiola summoned Götze from the bench, with the ineffectual Thomas Müller making way in the 64th minute. Bayern duly upped the ante, but there was no beating Karius, whose outstretched leg denied Franck Ribery.
The Bundesliga leaders had scored at least once in every league game this season, however, and it was Schweinsteiger who ensured that remarkable run would continue, the battle-axe midfielder arriving unmarked to head home Xherdan Shaqiri's cross with eight minutes left to play. Götze then got in on the act himself, rifling into an empty net to extend Bayern's unbeaten top-flight run to 51 matches ahead of Tuesday's possible title-clincher away to Hertha Berlin.
Line-ups and statistics
With the two goals in the dying minutes of the game against Mainz, Bayern are 'just one step away' from winning the title, watch the video courtesy of the official Bundesliga YouTube channel: