Arsenal are trailing 1-0 (3-2 aggregate) at the Allianz Arena as the second half goes on.
Bayern Munich have finally found the back of the net via a header from Joshua Kimmich.
Bayern's first attempt was sent over the bar but a play from the left side got them back on target.
Kimmich darted into the right position and perfectly headed the ball in, much to the confusion of Arsenal players.
But who is to blame for that goal?
Call it a collective let-down or even a rookie mistake, Arsenal players were all focused on shutting down Raphael Guerreiro on the left.
With everyone - the defenders and the midfielders - focused on Guerreiro, Kimmich used speed to his advantage to reach the right position.
By the time they realise what's happening, Kimmich has already headed the ball in.
Arsenal have conceded an unnecessary goal and now need a strong answer to get back in the game.
