The Gunners fell behind in the first half after Arjen Robben’s superb opener but Alexis Sanchez managed to restore parity in the first leg of their last-16 clash before half-time.
The Chile international scored at the third attempt after his penalty was initially saved to net what appeared to be a vital away goal for the visitors.
However, Bayern stormed back into a commanding lead thanks to second-half goals from Robert Lewandowski, Thomas Muller and Thiago Alcantara.
Writing in his Daily Mail column, Keown discussed what he found particularly worrying about Arsenal’s 5-1 loss at Bayern ahead of their trip to Sutton united in the FA Cup fifth round this weekend.
“With not even 24 hours behind us, how many people thought Arsenal would beat Bayern? What I was concerned by was the ease at which Bayern won the game. It looked like Arsenal had given up.”
Arsenal have never won the Champions League and have failed to reach the last eight of the competition since 2010.
The Gunners are in fourth place in the Premier League table.
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