Atletico Madrid boss Diego Simeone was angry with Real Madrid captain Sergio Ramos after Saturday's 0-0 draw.
Ramos allegedly made a comment about the linesman's mother, the same comment made by Diego Costa when he received a red card against Barcelona and a subsequent eight-match ban, yet nothing was done by the referee in the Madrid derby.
"What happens on the pitch stays on the pitch, but the linesman knows what he said," Simeone said when asked about Ramos' comments.
In terms of the game itself, Simeone recognises that a stalemate was probably a fair result.
"In the first half we were dominating the game and we couldn't find any solutions [in finding a goal] at the end," he noted.
"We're having a hard time in that aspect. In the second half, [Jan] Oblak saved [Karim] Benzema's header.
"It was a tight game, with both of us missing what it takes to win the match."