Mainz's Bo Svensson plotting a historic escape with a better record than Jürgen Klopp and Thomas Tuchel

Yet those who have followed the 05ers' transformation since Bo Svensson took charge at the start of January would call his team's win over the champions-elect anything but a shock. A surprise, perhaps, but when full context is provided, there was no David downing Goliath at the Opel Arena on Saturday, but rather an in-form team, oozing confidence, getting a deserved win over a side who need just one win from four games to clinch the title.

Hansi Flick's men will go again for those three points in a fortnight's time, but for Svensson's troops, the margin for error was finer; victory was imperative, and nobody can deny they deserved it.

"Mainz did very well, defended aggressively and kept it tight," acknowledged Flick. "We hardly had a chance to score, they defended their goal outstandingly."

Watch: Highlights of Mainz's win over Bayern

They did so as a team who not only knew how important three points would be, but one who signed a pact three months ago: to do what no club had ever done before, by avoiding relegation from a seemingly hopeless position.

In fact, not only did the outlook appear bleak for Mainz at the midway stage of the season, when they had just seven points and were eight adrift of the relegation play-off berth, they should have been goners. Historically, no club has ever recovered from such a dismal first half of a Bundesliga season to stay up, and while Mainz have not done it yet - and they will not welcome any premature congratulations - Saturday's win means they have their destiny firmly in their own hands.

The transformation was not immediate, however. Svensson arrived after a 5-2 defeat at Bayern, inheriting a team with just six points. Derby defeat to Eintracht Frankfurt followed and, while there were some much-needed promising signs in a 1-1 draw at Borussia Dortmund, a 2-0 loss at home to Wolfsburg left them with a mountain to climb.

If seven points from their first 17 games of the season was relegation form, the 27 they have picked up in 13 games since - bearing in mind also that they still have a rearranged game against Hertha Berlin to fit in - would have them on course for the UEFA Champions League. Only Bayern (32), Frankfurt (29) and Wolfsburg (27) have picked up more points on the run home, and all three have played one game more than Svensson's miracle makers.

To add further context, Svensson's record even eclipses those of arguably the first two coaches most people think of when reflecting on Mainz: Jürgen Klopp, currently manager at Liverpool, and Thomas Tuchel, who is now calling the shots at Chelsea.

As a Mainz player, Svensson spent one season under Klopp and six under Tuchel, and he recognises how much of their styles rubbed off on him. "Both the content and also their human aspect - a lot has stuck in my mind," Svensson said. "Things like how to deal with people, how to lead a team - that sparked my desire, while still a player, to become a coach. I was able to take on a lot from both of them, on all levels."

He has copied their success and improved upon it. With an average of 1.75 points per match, the Dane is doing even better than the 1.71 Tuchel averaged when he led Mainz to fifth and into the UEFA Europa League in 2010/11, and significantly better than the 1.26 Klopp averaged in his first Bundesliga campaign with Mainz in 2004/05.

Saturday's win over Bayern showed just how much Svensson had learnt from his peers, with an aggressive pressing game and quick transitions that both Klopp and Tuchel would be proud of. He knew the defence needed strengthening and, with the astute signings of Danny da Costa and Dominik Kohr, he has managed to halve not only the amount of goals Mainz have been conceding, but also the number of chances they have been allowing.

Stefan Bell did not even get a look-in under any of Svensson's predecessors Achim Beierlorzer, Jan-Morirz Lichte and Jan Siewert on the Mainz bench this season, but since he was installed in the heart of a three-man defence, Mainz's fortunes have transformed. It was just one of the many masterstrokes Svensson has delivered over a fantastic four months.

Their success has even forced an unexpected, yet very welcome rethink.

When Svensson returned to Mainz together with former coach Martin Schmidt and sporting director Christian Heidel after a round of phone calls on Christmas Eve, none was under the illusion that the priority was anything other than building a team capable of bouncing straight back following inevitable relegation.

Now on a seven-game unbeaten streak, including three wins in a row, Mainz need to finish the greatest escape act in the history of German football before changing their planning to focus on yet another season in the Bundesliga. But with a trip to Frankfurt followed by games against Champions League-chasing Borussia Dortmund and Wolfsburg, there is still work to be done.

The hard part has been done, though, and with a five-point advantage over 16th-placed Cologne, including a game in hand, Mainz are within touching distance of doing the unthinkable.

In that context, beating Bayern was one of the most normal things Mainz have done in 2021.