The Clasico between Barcelona and Real Madrid, Spain's biggest football match, has been postponed due to protests in Catalonia, the Spanish Football Federation (RFEF) announced on Friday.
The two clubs have until 0800 GMT on Monday to find a new date, which will be decided by the RFEF if they cannot reach an agreement.
The original fixture was due to take place at Barca's Camp Nou on October 26.
FC Barcelona and Real Madrid must agree on the new date of the meeting before October 21," an RFEF statement read.
"In case of not reaching an agreement, the Competition Committee will be responsible for determining the date of the meeting."
Two dates reportedly being considered are Wednesday, December 18, when other Spanish teams are involved in the Copa del Rey, and Saturday, December 7.
The Clasico was set to be Barcelona's first home game since nine pro-independence leaders were sentenced to imprisonment on Monday for their role in the illegal referendum over Catalan independence in 2017.
The ruling has sparked violent demonstrations across the city and there were fears protestors would use the match against Madrid to stage further acts of unrest.
Barcelona's football club, which is regarded as a symbol of Catalanism, responded on Monday with a statement insisting "prison sentences are not the solution".
La Liga then proposed to the RFEF that the venue of the Clasico be changed from Camp Nou to Madrid's Santiago Bernabeu but neither club were keen to accept the switch.
"The RFEF agrees to dismiss the request made by La Liga in relation to reversing the order of the matches played between Barcelona and Real Madrid," the statement added.
Instead, it has been decided that a change of date is necessary due to what the RFEF described as "exceptional circumstances".
After the Catalan independence referendum in 2017, Barcelona played a league match against Las Palmas behind closed doors in protest, after their request for a postponement was rejected.
Barca play away at Eibar in La Liga on Saturday and planned to make the 589-kilometre journey by bus to avoid demonstrations at El Prat airport.
Real Madrid also play on Saturday, away at Real Mallorca.