This guy made so many blunders that led them to concede goals
On top of my head, for El Classico games only:
Made that failed overhead kick attempt that gifted Titi Henry's goal (2-6 famous victory)
Last season when he played Suarez onside that leads to the winner (1-2)
The first and the fourth goal on that 0-4 drubbing where he was all over the place
Feel free to add some more