Union were never supposed to trouble the reigning champions; Bayern aren’t the yardstick that they would, or will, measure themselves by this season. Indeed, the fact that they were here at all - at the spotless Bayern Campus, with a ragged group of utterly indefatigable fans – tells enough of a story. But still this hurt, and as the players trudged off at half time, 3-0 down, you could see just how much.

And it clearly saw them redouble their efforts in a second half that saw the hosts score only the once more, and that a slice of horrible fortune on their part.

This was very different to Union’s 4-1 loss at home to Wolfsburg on Tuesday, because they knew that result had flattered their guests. But Bayern are better than Wolfsburg. They are the best team in the land, and  it showed.

However, despite this, and despite their injury woes, it didn’t look like they were scared; Union came out sharply. They had been superb in the first half on Wednesday, and they were full of courage here with Katja Orschmann stepping up to pressure Momoko Tanikawa, and Antonia Halverkamps doing the same to Franziska Kett, early on. Celine Frank was back quickly to intercept Kett’s pass across the edge of the box.

But for Nadine Böhi it was to be quite the baptism of fire. She had never started for Union before. She’d never played in the Bundesliga either; so, this was quite the night to do it. She had been on the bench throughout the EUROs for a heroic Swiss team, and Ailien Poese said before kick-off that she had never stopped working, had never let her head drop, despite her lack of minutes at her new club.

It wasn’t easy, but she dealt with her first challenge - her first touch - superbly, coming out to Jovana Damnjanovic as the Bayern striker darted onto a clever through ball.

But it was to be a busy evening for the keeper.

After her intervention on Damnjanovic, Böhi struggled to hold Kett’s cross from the left, from where Linda Dallmann drove home the flying ball to make it 1-0 after only ten minutes.

Dina Orschmann was soon seen flying up the left wing, but Bayern were seizing control of the ball now, and Klara Bühl put her header wide when Dallmann found her from the right.

Böhi then did well after 16 minutes to get down and save from Tanikawa, put through by Pernille Harder’s trickery at pace, dancing on the ball. She would, however, have no chance when Harder made it 2-0 for the hosts after almost 20 minutes. Giulia Gwinn had made the most of some chaos in the box, and a bouncing ball out on the right, clipping the ball in, where the Danish superstar headed it down into the ground, and over the Union stopper.

Dina Orschmann came close for Union, next up. Having marched a few steps forwards, she looked up and cracked a shot at Maria-Luisa Grohs, getting enough on it for the keeper to spill the ball as it bounced out of her grip.

But at the other end, Böhi was getting a real work out; she held Harder’s next shot at the second attempt, but Bayern would be three up with only 25 minutes played after Bühl attacked down the right. She crossed and found Gwinn, who volleyed home.

Union refused to buckle just like that. They held their shape, they stayed compact and always looked to cover every runner, but Bayern players came from all sides – they weren’t so much attacking as swarming at times - leaving the Union players chasing shadows. Stine Pedersen, Tanikawa and Georgia Stanway were knocking the ball about for fun, stretching and pulling and testing Union’s back five. When they won a corner on the right, it was played short to Glodis Viggosdottir, who cracked an effort, first time, that flew just wide.

They had more chances; Böhi held Tanikawa’s drive, getting her body behind the ball.

When Union won a free kick, not far inside the Bayern half, Katja Orschmann hit it hard and flat, diagonally towards her twin, Dina. Grohs, however, got there just in time. The pair of them looked ashen-faced at the break. They all did. It had been chastening, to say the least.

If Union were unchanged coming into the second half, so were the patterns of play – at least initially. Bayern started with Gwinn finding Dallmann, who played the ball back to her international teammate with the most carefree of back-heels.

Two minutes later the pair had combined again, but this time the former’s return pass was cruelly hit into her own goal by the sliding Tomke Schneider. There was little she could do about it - she was already sliding - and the ball travelled in slow motion off her and past the unsighted Böhi.

They could have rolled over, and it is to Union’s great credit that they refused to. Indeed, Böhi and her teammates reduced the hosts chances to a minimum after that, despite the possession stats reading 70/30 in their favour. Schneider make a wonderful challenge on Damnjanovic ten minutes later; as she scuttled back into place to cover as Harder crashed a shot into Samantha Steuerwald. Böhi then made an equally impressive stop, diving to tip Katharina Naschenweng’s goal-bound effort awaypastthe top corner. 

With an hour gone, Poese made her first changes. Katja Orschmann, Schneider and Weidauer were replaced by Alma Aargaard, Judith Steinert and, also making her Union debut, Marina Georgieva, but more worryingly was the next swap, forced upon her. Dina Orschmann was off after 68 minutes, having needed treatment on the pitch, the only solace being that her replacement, Nele Bauereisen, herself, was coming back from an enforced layoff.

Union’s injury list is already 14 names long. It didn’t – doesn’t - need adding to.

With under ten minutes to play, Union had their best period of play. Georgieva stepped up, Bauereisen strived on the inside right, and ultimately Heiseler – after Frank’s clever leave – crashed a shot, heading under the bar, that Grohs did well to hold.

Böhi had done well in the second half, and she saved Naschenweng’s shot, having flicked the ball back over her own head, with certainty. Steuerwald then headed Alara’s shot off the line, but that was it.

Böhi stepped up for the post-match interview without flinching. She and her teammates had been taught a lesson, but  there was no shame in it. This one had never been a must-win after all.