The Premier League leaders' performance underlined why they remain the Champions League’s last team with a 100 per cent record. Their pressing structure suffocated Bayern’s build-up, their set-piece dominance caused repeated problems, and their transitions exploited every defensive gap left by Kompany’s side.
For Bayern, the defeat ends an 18-match unbeaten run and exposes cracks that had not been punished in earlier European fixtures. After impressive wins over Paris Saint-Germain and Chelsea, they were second-best in intensity and duels, areas usually considered Die Roten's strengths. Even with 12 points from five matches, their hold on top spot in the group is no longer guaranteed.
The Gunners, meanwhile, have now established themselves as genuine contenders for the Champions League’s latter stages, the only club still boasting 15 points from 15.