Barcelona: Real Madrid captain Sergio Ramos said Barcelona forward Lionel Messi put pressure on the referee at halftime in Sunday's thrilling Clasico at the Nou Camp which ended 2-2 after a series of controversial decisions.
Barca defender Sergi Roberto had been sent off right at the end of the first half for clashing with Marcelo, provoking fury among the home side's players and supporters as moments earlier Real forward Gareth Bale had got away with a studs-up challenge on Samuel Umtiti.
The Wales forward later denied Liga champions Barca victory by hitting a scorching late equaliser from outside the area.
The constant on-field confrontations and meaty challenges led to referee Alejandro Hernandez dishing out eight yellow cards, including booking Ramos and Barca striker Luis Suarez.
"Messi put him under a bit of pressure in the tunnel, I don't know if there are cameras, maybe he caused him to referee in the second half in a different way," Ramos told reporters.
"He said everything to him. This is football and everything should stay on the pitch."
Ramos also said he thought Suarez had been exaggerating his pain when the Uruguayan striker went down after a challenge in the first half.
Real did not put the ball out of play at the time, angering Barca players.
"When an opponent is down on the floor and you think it's serious you normally kick the ball out of play. But I know him a little and I know what he's like," Ramos added.
"We always respect Barcelona but in that play I thought kicking the ball out was not necessary."
Suarez also had a goal ruled out for offside, while Madrid were denied a late penalty when Marcelo was tripped in the area by Jordi Alba.
"We watched an incredible game of football and I can't say if the draw is fair or not," said Real coach Zinedine Zidane, who would not be drawn on the referee's performance.
"Those that came to the stadium will go home happy. The game had a little bit of everything, I imagine it was very tough to referee."