That is according to player-turned-pundit Gary Lineker.
Much has been made over Arsene Wenger’s future at the club with the manager weighing up whether to extend his stay at the Emirates beyond the summer.
His Gunners team have fallen away in their latest bid for the Premier League title, and Bayern pose as a daunting prospect in Europe this week.
Arsenal travel to the Allianz Arena tomorrow (7.45pm), where a heavy defeat is set to leave supporters more opposed to Wenger continuing.
Arsene Wenger is mulling over his future at Arsenal with his contract set to expire this summer
Lineker outlines the Gunners fanbase has been left totally split in a similar sense to Brexit, and a Bayern win will pile on further pressure.
“They were unlucky with the draw, as they have been consistently over the last few years, but they are not playing well,” Lineker told the Mirror.
“It will be tough against Bayern, and they will be second favourites, but it could define their season in many ways.
“If they go out in the last 16 again, the fans will get restless because they are massively divided.
Arsenal face a huge test at the Allianz Arena tomorrow night against Bayern Munich
Arsenal line-up predicted to face Bayern Munich
Mon, February 13, 2017
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“It’s a bit like Brexit – there is no middle ground. I just fear that would be exacerbated by defeat to Bayern Munich, especially if they stumble in the Premier League.”
However, should Arsenal pick up a positive result in Germany, Lineker points out their fortunes could change.
The Gunners sit fourth in the Premier League table, 10 points off leaders and London rivals Chelsea.
And while Lineker feels chasing down top spot is too much to ask, qualification for the Champions League again would be well within reach following a famous European victory.
Gary Lineker doesn't believe Arsenal can catch Antonio Conte's Chelsea
Admittedly I can’t see them catching Chelsea in the title race
He added: “But if they go through, it gives them a big boost – and if they can beat a side like Bayern, I think you’d see their league form improve as well.
“They are still in three competitions, so they have got something to fight for on three fronts.
"Admittedly I can’t see them catching Chelsea in the title race, but it’s important they stay in the tie at the Allianz Arena because, statistically, it helps a bit to have the second leg at home.”