The Gunners, who have been eliminated in the first knockout round of the competition in each of the last six seasons, twice by Bayern, not only conceded five goals but over 75% possession in Germany.
Their challenge lasted until the break thanks to Alexis Sanchez, who followed up his own missed penalty to equalise after Arjen Robben’s superbly-struck 25-yard opener.
But after Arsenal lost Laurent Koscielny to injury early in the second half, Bayern ran riot during a 10-minute period in which Robert Lewandowski headed home before Thiago Alcantara scored twice. Substitute Thomas Muller rubbed salt in the wounds with a late fifth.
It leaves Arsenal with a near impossible task in the second leg and heaps more pressure on manager Arsene Wenger, who now only has the FA Cup as a realistic source of silverware in what will go down as another failed season.
For the first time in five seasons, the Gunners claimed top spot in their group (ahead of PSG, who made this achievement even more impressive with their demolition of Barcelona on Tuesday) but nonetheless they were drawn against the Germans – their last-16 conquerors in both 2012-13 and 2013-14.
It is damning, really. These two clubs have similar resources, and are both notional “super clubs”, but Bayern so often prove themselves superior. There can’t be two such sides that have met so often in such a short space of time to see no deviation in terms of what happens. They have been drawn together four times in five years, and Bayern are now certain to finish on top four times.
The game was up and, after temporary respite due to the weekend win over Hull City, it will raise more questions over whether Wenger’s time should be up too. It is his dream to win the Champions League but that looks an utter fantasy. Arsenal have never been so far away.
Bayern had already raised the bar, though.