Another 45 minutes later, everyone in Munich colours was hugging each other. Nicolas Jackson, Michael Olise, Jamal Musiala and Harry Kane had in all seriousness turned this Bundesliga contest on its head into a 4-3 victory, which more than anything acts as a psychological boost for the Champions League semi-final first leg at Paris Saint-Germain on Tuesday. “I love this mentality,” stated head coach Vincent Kompany afterwards.

“The boys celebrated like we’d saved ourselves from relegation.”Worst half of the seasonBut before they could celebrate, Bayern endured their worst half of the campaign so far. With a much-changed line-up, including a first start for 18-year-old Bara Ndiaye, it was only in the first quarter of an hour that the visitors managed to show something resembling the dominance everyone had expected. Mainz were then rewarded for a disciplined display, in which they countered with speed and purpose: a loss of possession in Bayern build-up and suddenly it went in the other direction.

“What went wrong in the first half? Everything!” Kompany responded in the post-match press conference. “It felt like it could’ve been four or five before the break.”What Mainz did particularly well: with just a few touches of the ball, they bypassed the complete pitch and got their attacking players into clear shooting positions.

“We kept managing to escape by being brave in our passing. We made correct, good decisions and were dangerous again and again,” praised coach Urs Fischer. The stats were clearly in the 10th-placed hosts’ favour, with 11 attempts on goal to two.

Three of those ended up in the back of the net, while Bayern were not up to the mark at times, too passive, too uninspired – and clearly shocked by the goals conceded. Not a single Munich shot was on target. “We didn’t get into the penalty box – we had a lot of possession, lots of short passes but didn’t get in on goal,” criticised Kompany.

“That can happen sometimes, but then you shouldn’t concede.”Granted, maybe falling behind was almost understandable in the current period, with Bayern juggling routine Bundesliga matches in between securing the title last weekend, reaching the DFB Cup final and with an eagerly anticipated Champions League semi-final coming up. Nevertheless, the visitors were disappointingly 3-0 down at the break – for only the fourth time in this millennium. What happened next was described by Mainz playmaker Nadiem Amiri as “absolutely shocking”.

His coach, Fischer, added: “It’s still hard to find the right words. But it’s easy to summarise: we played a top first half and then almost stopped in the second half.”Morale, will to win, team spiritThe strength of Bayern’s character, will to win and team spirit was revealed in the second half in a remarkable, unique and unforgettable way. Kompany certainly found the right words in his loud half-time team talk and brought on three goalscorers in Kane, Olise and later Musiala.

“The quality that was unleashed after that – you can’t defend against that. It’s the best example of why Bayern are the best team in the world at the moment,” continued Amiri.The 05ers may have had the first shot on goal of the second half, but it was virtually one-way traffic after that. The lively Olise in particular was a constant menace for the hosts, as Bayern’s passing game became more and more accurate, the gaps in the Mainz defence became bigger and the potential counter-attacks were quickly snuffed out by FCB.

“We spoke at the break about not retreating, not thinking about just defending the 3-0 lead – but that’s exactly what happened,” bemoaned the Mainz boss. “Bayern are just too good this season, too strong.”The consequence: Jackson quickly reduced the deficit with his seventh league goal of the season, sparking hopes of a historic comeback. Even the mighty FC Bayern had only once before come from 3-0 down to win: against VfL Bochum in 1976 (final score 6-5).

When Olise stroked the ball into the net in his own inimitable way with his magic left foot, and the brilliant Musiala levelled the score at 3-3 just minutes later, the turnaround was complete. Everyone could see the energy that these goals released in Musiala’s unrestrained celebration, in the look of pure joy on his face. “The celebration, the smile – when an attacking player shows that, everything’s released,” said Kompany.

“Then everything’s all right. It’s the first time that Jamal is feeling this freedom again.”Bayern come from behind to beat MainzThree goals in ten minutesOnly the Bayern fans could still be hard at the MEWA Arena, the Mainz supporters – like their players – were in a state of shock. A win, which would have been the fifth in the last six home games against Bay