Casillas called Xavi after brawl in El Clasico and Mourinho did not like it. The Special One believes Iker's girlfriend leaked a lineup to the press.

Iker Casillas thought he was doing the right thing when he called Xavi after all hell broke lose in a game between Real Madrid and Barcelona. Little did he know, that was the worst thing that he could have done if he still wanted to be respected by Jose Mourinho. 

The two will meet again for the first time as opponents. They have been rivals for a while now, ever since Iker made that call in 2010. At that time, the Spanish goalkeeper called Barcelona's captain to vent on how things got ugly after the game. Xavi, tried to calm him down and they ended up agreeing that those brawls should not be a part of Spanish football. 

‘He called me and [Carles] Puyol. I told him that both sides had to look at themselves. He was looking out for the interests of Spanish football,’ Xavi said.

WATCH: The fight that started it all

That was considered treachery in the eyes of the Special One. In the following years, Casillas was not able to change Mourinho's mind and his time on the bench just kept increasing. For Mou, making friends with the enemy was not part of his script. He wanted to go to war against Barcelona.

One of those wars ended with a 5-0 scoreline in favor of Barcelona. The Cules gave Mourinho what he called "the worst defeat of his career". A similar scoreline did not happen in the following games, but Barcelona's dominance did continue. 

In a game played in April, both sides tied 1-1. While Mou was not happy with the outcome, what was even worst was knowing that a reporter had leaked the lineup to Marca way before the game. Sara Carbonero, Iker's girlfriend was the main suspect in this case.

The famous phone call happened after a brawl in the Spanish Super Cup before the 2011-2012 season started. Casillas did not hold back on the fight started with a foul from Marcelo on Cesc Fabregas. What Casillas did the folllowing day after looking at the footage of the fight, entered him in the list of traitors under Casillas eyes.

Now, four years after that fight, Casillas and Mourinho will meet again. The goalkeeper won't have to listen to Mou's instructions. This time, they represent different clubs. They both want to win and while they might never leave the hate for each other behind, these two big soccer legends may establish their differences on the field.