Ronald Koeman was not a happy man after Barcelona squandered the chance to go top of La Liga with defeat in El Clasico. The Dutchman was furious that referee Jesús Gil Manzano refused to give a penalty for Ferland Mendy's challenge on Martin Brathwaite. Karim Benzema and Toni Kroos had put Real Madrid in control, with Oscar Mingueza scoring Barca's consolation. It was a bitterly disappointing night for Lionel Messi, who has now failed to score in seven successive Clasicos. In fact, he's drawn a blank in the fixture since Cristiano Ronaldo left La Liga.As much as Barcelona lacked their usual spark, however, Koeman was intent on blaming the officials for his side's defeat. Gerard Pique, likewise, furiously confronted Manzano at full-time on the pitch. You can see Koeman making his way over to speak to him below: 

In addition to being denied a spot-kick, they also expected more time to be added on, but he blew the whistle exactly on the fourth minute of added time despite there having been a stoppage to fix the referee's equipment. 

A report from El Chiringuito TV and journalist Juanfe Sanz Perez claims the altercation between Koeman, Pique and Manzano continued into the tunnel. 

Perez said the Barcelona duo were "screaming" at Manzano and that "heavy words" were used, before Real Madrid players ultimately had to intervene to stop the situation. 

It's not the first time Manzano has upset Barcelona, of course. 

This is the same referee who sent off Messi in the Spanish Super Cup against Athletico Bilbao. The official also gave red cards to Neymar and Luis Suarez during their time at the club. 

On this occasion, Barcelona had little real justification to be so irate. 

Casemiro was also sent off for Real Madrid late on for two rash challenges within just minutes of each other.

It all means that for now, at least, Real have gone top of La Liga, surpassing Barca and Atletico Madrid.