Jeremy Mathieu says he knows how Clement Lenglet is feeling after his mistake cost Barcelona two points against Cadiz on Sunday.
Lenglet gave away a late penalty, which was converted by Alex Fernandez, as Barça were held to a surprise 1-1 draw at Camp Nou.
Former Barça defender Mathieu says Barça can be a lonely place at times and says he found himself in a similar position in his final season at the club.
"I had a really tough time in my last year at Barcelona," he told Catalunya Radio. "I felt like the defeat in Turin (against Juventus, 3-0) was my fault, but I don't know why they killed me (for it).
"As I see it, 11 people play football. But I am strong, it doesn't matter and I left to enjoy myself at Sporting. At Sporting they talk to me when something happens, but at Barça, nothing at all.
"I needed a little affection. For example, when I made a big mistake in the game against Malaga, no one spoke with me. Not even (then coach) Luis Enrique. I didn't speak with him for the whole year.
"I felt alone in the dressing room. No one supporting you... for me, that's not football. Everyone is killing Lenglet now. I know how he feels. Everyone kills you. You have to try and be positive to turn it around."