Atletico Madrid striker Diego Costa was given a straight red card in Saturday's 2-0 loss to Barcelona at the Camp Nou for crude remarks he made about the match official's mother, according to referee Jesus Gil Manzano.
Costa was shown a straight red card in the 28th minute of the top-of-the-table clash for a verbal outburst at Manzano, who later reported the contents of the ex-Chelsea man's derogatory message in his match report.
With a man advantage for over an hour, Barca finally found a breakthrough with a wonderful curled strike from Luis Suarez in the 85th minute and Lionel Messi sealed the win with a goal moments later.
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After the match, Atletico coach Diego Simeone cursed his side's bad luck with refereeing decisions in games against Barcelona
"I asked the referee if what he said was so bad because we have seen Barca players do the same thing, saying things right in the referee's face and they did not get sent off, they got away with it," Simeone told a news conference.
"If Costa really said what the referee claims he did, then he was correctly sent off, but we must be doing something wrong as we have had seven players sent off in 11 games.
"I remember we had Fernando Torres, a global icon, sent off here for making two fouls."
Atletico midfielder Koke also aired his frustration.
"We were doing so well until the red card but all the small details went their way," he said.
"Whenever we come here something strange happens, we've had a lot of red cards against Barca and not all of them have been fair."
Atletico coped well with 10 men and had one glorious opportunity to break the deadlock in the second half from a free kick but midfielder Rodrigo headed narrowly over the bar.
"The plan was to close space through the middle and invite the opponents to play on the wings so we could have a tiny possibility of winning," Simeone added.
"We were better in the second half, we made a huge effort and I felt we were in control until the final five minutes when Suarez got the breakthrough. I'm left encouraged by many things which my team did today."
Meanwhile, Barcelona forwardSuarez said his side had taken two steps towards wrapping up the La Liga title with the win.
"Today we didn't just take one step, we took two steps forward, we obviously have a very big advantage now but there are still some games to go and it could still get difficult," Suarez told reporters.
"This was another game which shows just how hard it is to win the league and we deserve a lot of credit for what we're achieving."
Defeat by Atletico would have trimmed Barca's lead to five points and coach Ernesto Valverde underlined the importance of the victory.
"These three points were very important, we still have to finish the job but today's game was fundamental and could mean a lot," Valverde said.
"We're very happy because we know exactly what Atletico are, an enormous team who scrapped until the end with 10 men. We were giving everything and Luis' goal was like a shot of adrenaline."
Having taken a huge step towards the title, Barca can now focus on their Champions League quarterfinal first leg against Manchester United on Wednesday and Valverde said he would have to rotate his squad.
"We have a lot of games coming thick and fast and we'll have to call on the entire squad, that's a reality," Valverde added.
"Bur our idea is to compete on all fronts because we still haven't won anything."