Gunners UEFA Champions League hopes lie in apparel at the last - 16 stage yet again following a first - leg strike at Bayern Munich.
Arsenal, who have been removed in the first knock - out round of the tournament in each of the last six seasons, two times by Bayern Munich, not only conceded five goals although over 75% possession in Germany.
Arsene Wenger side challenge persist until the half - time thanks to Chilean winger Alexis Sanchez, who followed up his missed penalty to adjust after Bayern winger Arjen Robben's delightfully - struck 25 yard opener.
Although after Arsenal lost defender Laurent Koscienly to injury early in the second half, Carlo Ancelotti side ran uprising during a 10 - minute period in which Polish striker Robert Lewandowski headed home before Thiago Alacantra netted double. Substitute forward Thomas Muller added with a late fifth.
It leaves the Gunners with a near hardly possible task in the second leg and pile more pressure on boss Arsene Wenger, who now only has the FA Cup as a sensible source of silverware in what will go down as one more abort season.