The two teams have until Monday to reach an agreement on a new date for the LaLiga clash, the Spanish Football Federation (RFEF) announced on Friday, reports Efe news.
If they cannot agree on a fixture before 8 am GMT on Monday the RFEF will set a new date. The decision came in the wake of unrest in the city of Barcelona after Catalan separatist leaders were jailed on Monday.
LaLiga had previously requested that the game be held at Santiago Bernabeu instead of Camp Nou. The RFEF rejected a request to change the location of the game, a proposal that both teams had refused.
LaLiga has proposed the game to be played on December 7, while the RFEF suggested that it take place on December 18.
Madrid has agreed to play on December 18, while Barcelona has insisted on maintaining the date initially set for the game.
Madrid coach Zinedine Zidane said: "In the end, we will do what we are told If we play it on October 26 so be it, but if the date changes, we will adapt."
He added: "I have a preference but I will not say it. We know it can be on 7 or 18 December and we will be prepared."
Once the first LaLiga request was turned down, the RFEF considered LaLiga's other proposal, which was agreed by the RFEF's general secretary Andreu Camps.
The RFEF has accepted the proposal and also called on both clubs to reach an agreement before Monday.
( With inputs from IANS )