José Mourinho, the Real Madrid coach, managed to open a small crack inside Barcelona, and he probably didn't expect the impact to run this deep. His plan may have gone no further than handling things in a normal manner, something that rarely counts against you in football.
According to the Spanish newspaper "AS", the Clásico result left its mark on Hansi Flick in several ways. He had tied the Paris Saint-Germain fixture to the Clásico and ended up losing both.
Tactically, Barcelona lost their balance against Real Madrid. Once the 1-2 defeat was confirmed, the German coach fell back on the familiar excuse of players lacking physical readiness and recovery.
There seems to be more to it behind the scenes. Wednesday brought a team meal to strengthen the bonds within the squad, and when that happens, it usually points to issues that need thrashing out in the dressing room.
Barcelona's board surprised everyone on Thursday, slipping an affirmation of "full confidence in the team and the coaching staff" into its media statement.
That phrase almost certainly carries little weight, yet it was striking, even dressed up as praise for the team.
Friday brought another twist. The German coach opened the door to signing a new player in the January window, a matter that had been on ice since the summer.
Every one of these developments landed within days of the Clásico defeat.
Lamine Yamal escaped none of the criticism. Some quarters reproached him for travelling to London alone on Sunday evening, on a separate trip from the official one the club organised on Monday morning, and the Barcelona fans' association in the stands was also temporarily closed.
The one complaint Barcelona fans kept repeating about Flick across his first two years resurfaced too: his players' inability to control themselves in difficult situations.
Everyone remembers the second leg against Inter Milan in the semi-final, with Barcelona sitting pretty at 3-2 up. Everyone remembers the poor management of the quarter-final second leg against Atlético Madrid at the Metropolitano, when the team did the hard part and went 2-0 up inside 25 minutes.
Flick's display in the last match was puzzling. He had grown used to emerging from the small crises he faced at Barcelona, such as the disastrous spell of November 2024, as well as the 4-0 defeat in the first leg of the Copa del Rey semi-final and the loss to Girona that followed.
Each of those crises played out much like this week: internal talks, collective meals and other moves. The coming days will reveal just how big the crack is that Mourinho has opened inside Barcelona.