"You wouldn't know about switching marking responsibilities on the pitch because you were never a player," the defender allegedly said after being blamed for Carles Puyol's goal
And tensions now appear at a high amid reports of a serious training ground dispute between coach Jose Mourinho and vice-captain Sergio Ramos on Friday.
According to Madrid-based sports paper Marca, Mourinho accused his playing staff of betrayal following their post-match press reaction on Wednesday night.
During Friday's session, Mourinho is reported to have turned to Ramos and said: "You [guys] killed me [with your quotes to journalists] in the mixed zone."
Ramos is said to have replied: "No, boss, you only read what was published in the press, not everything we said."
According to Marca, Mourinho then hit out at the supposed Spanish clique as he responded: "Of course, as you Spanish are world champions, your friends in the press protect you ... like the goalkeeper."
That was in reference to captain Iker Casillas, who was some 30 metres away and apparently reacted angrily as he protested: "Boss, here we say things to our faces, eh ..."
Mourinho then reportedly turned to Ramos and asked: "Where were you for the first goal, Sergio?"
"Marking [Gerard] Pique," he answered, to which the Portuguese countered: "Well, you should have been marking [goalscorer Carles] Puyol."
Puyol was allowed a free header by Pepe, who lost the Barca captain at a corner, and Ramos claimed he and his team-mate had switched marking duties prior to the set piece.
"He [Puyol] and Pique were blocking with screens [to leave space for others] and we decided to change the marking [responsibilities]," the Sevilla-born star is said to have told his trainer.
"What's this then?" Mourinho snarled. "Now you're trying your hand as coach are you?"
"No, but depending on the match situation, sometimes it's necessary to change the marking," Ramos hit back.
"And as you have never been a [professional] player, you wouldn't know that this is sometimes necessary."
Marca also claims the Madrid players remain unhappy after Mourinho's attack on his players following the Christmas holidays, when he said some of them had not stopped 'eating and drinking' during the break.
The paper also alluded to preferential treatment to the Portuguese players on Mourinho's part, an action which has apparently upset his Spanish contingent.
In another damaging report on Sunday, El Mundo Deportivo claimed Pepe made a racist remark to Barca's Seydou Keita in the Spanish Supercopa back in late August, calling the Malian a 'monkey' - the same insult said to be used by the Catalans' Sergio Busquets against Marcelo in a Clasico clash in the Champions League last season.
Real Madrid and Barcelona renew their rivalries on Wednesday at Camp Nou, in the second leg of the Copa del Rey quarter-final, with the Catalans 2-1 up from the first match.