Real Madrid's loss to Arsenal was not just a normal defeat but a humiliation over the course of the two legs. The London based club absolutely embarrassed Los Blancos in both the legs and left no room for them to even think of advancing to the semi-finals.
One could say that Real Madrid were a bit unlucky in the first leg with the two extremely good free-kicks but the awful performance in the second leg cannot be discounted with any excuse.
Los Blancos had no plan whatsoever to win the tie and it was blatantly visible. The only philosophy they stepped in with was to cross the ball endlessly expecting miracles to happen.
But these plans would have substantiated if there was present an actual striker in the squad which Real Madrid direly miss. The front three has only wingers and no actual center forward who can take the ball and decide to smash it in.
Thibaut Courtois remembers former striker amidst goalscoring problems
If I am to submit a summary of what went wrong, it would be that Real Madrid simply could not score the goals they needed to glide through. And Thibaut Courtois, after the Bernabeu humiliation, was not oblivious to this very visible fact.
When asked about what went wrong, he said, "In the end, they [Arsenal] are a team that defends well, is well organized, presses well, and it's difficult to find space. We put in a lot of crosses, but this year we don't have Joselu, a natural striker up front."
It is absurd that the goalkeeper knows this, the fans know this, but the most decorated manager in the history of Real Madrid does not realize it. It was clear from the start of the season that goalscoring was a concern, but nothing changed. The board did not take action, and Ancelotti's techniques remained unchanged.
Now that it's too late, all they can do is share the blame. And again, the only option to set this right is to part ways with Carlo Ancelotti and make plans about reinforcements in the attack.