Thibaut Courtois slammed his team-mates for their "unacceptable" performance as Real Madrid were thrashed 4-0 by Barcelona in the Clasico on Sunday.
Barca extended their unbeaten run in La Liga to 12 matches and halted Madrid's charge to the title after a comprehensive victory at Santiago Bernabeu.
A brace from Pierre-Emerick Aubameyang and goals from Ronald Araujo and Ferran Torres sealed all three points for the visitors, with Courtois left frustrated by the Blancos' failings in defence.
What has been said?
The Madrid goalkeeper told Movistar: "Today we gave an unacceptable image for this club. There are players missing, but you didn't notice that it was them that played Thursday [against Galatasaray in the Europa League]. They found a lot of space.
"We weren't compact and weren't able to keep the goals out. For the first goal, they anticipate better at the front post and we're not switched on for the second either.
"After the break, we think we can come back, and after 10 seconds Ferran Torres is one on one with me..."
Courtois questions Ancelotti's tactics
Blancos head coach Carlo Ancelotti opted to play with a false nine in the absence of injured top scorer Karim Benzema, but the gamble did not pay off as the hosts only managed to record four shots on target to Barca's ten.
Courtois was surprised Ancelotti went with that set-up after seeing it backfire in the Copa del Rey quarter-final clash with Athletic Bilbao last month, but also admitted the players lacked "fight" in the second half.
"We will have to talk about the tactics internally," he added. "They haven't worked at the start of the game or the second half. We have to discuss it internally, not here.
"We played with a false nine in the Copa and hardly had any shots and it was the same here. We started OK, we had a chance with Fede Valverde which Marc ter Stegen saved well, but from there we dropped off.
"We didn't find the free man playing out and that makes it hard. Then in the second half, we cannot start like that. This badge demands that you fight and in the second half we did not. We could have lost by even more."