The Copa Libertadores final second leg between River Plate and Boca Juniors was originally scheduled to be played last weekend in Buenos Aires, but it was postponed after the Boca team bus came under attack from River fans.
South American football's governing body CONMEBOL on Thursday confirmed that the twice-postponed Copa Libertadores final second leg between Argentinian rivals River Plate and Boca Juniors will be played on December 9 at Real Madrid's Santiago Bernabeu stadium.
Originally scheduled for last weekend at River's Monumental stadium in Buenos Aires, it was postponed after some Boca players were injured when their team bus came under attack from their arch rivals' fans throwing projectiles.
Boca appealed to CONMEBOL's independent disciplinary committee to be awarded the trophy and have River expelled from the competition, but that was also rejected on Thursday.
Instead, CONMEBOL hit River with a two-game stadium closure "that will be applied from 2019" in official continental competitions, and "a $400,000 fine."
In a separate statement issued late on Thursday, Boca Juniors said it "did not share" the arguments of the CONMEBOL disciplinary panel and planned to appeal.
CONMEBOL president Alejandro Dominguez said that Real president Florentino Perez had offered use of the Bernabeu "for free."
"Madrid is the city with the biggest Argentine population in the world, outside Argentina," said Dominguez.
"It's the 10th safest city in the world, it has the airport with the greatest connectivity, and it's a city with a football tradition."
'No place for hooligans'
He added that fans of both teams would be admitted to the Bernabeu, something that was not the case for the original clash.
Away fans have been barred from stadiums in Argentina since 2013 due to football-related violence that has seen more than 300 people killed in the last 50 years, according to one charity.
Dominguez had a message to the hooligans, known as barrabravas in Argentina, should they be thinking off attending the match.
"The 'barras' should not even dream of going. There is no place for them.
"I'm sure the message that the fans are going to send is what the world is waiting for: that the good guys are going to win this time."
Several Boca players suffered cuts from broken glass and the effects of smoke inhalation following the bus attack on Saturday.
While CONMEBOL initially insisted the match would go ahead, the two sides' presidents agreed to postpone the second leg for 24 hours.
But a day later, Boca refused to play again, insisting they would be disadvantaged, and the match was indefinitely postponed.
On Monday, Boca petitioned CONMEBOL to be awarded the victory but a day later, the governing body said the match would go ahead "outside Argentina."
The Buenos Aires rivals drew their first leg in early November at Boca's iconic Bombonera arena 2-2.
The choice of the Bernabeu means that both the Copa Libertadores and Champions League finals will be played in Madrid within six months of each other.
The final of Europe's premier club competition will be played at the home of Real's own city rivals Atletico Madrid, the Wanda Metropolitano, on June 1.
Several cities and stadiums had been vying to host the prestigious all-Argentine final clash, dubbed a "superclasico" and the most important club encounter in the country's history.
Possible venues ranged from Genoa in Italy to Asuncion and even Qatar's capital Doha.
But Madrid won out, with Spain Prime Minister Pedro Sanchez tweeting that the country "is ready to organise the final."
He said Spain has "ample experience in such events and is already working on the necessary deployment to guarantee the security of the event."
The Bernabeu has a capacity of more than 80,000 seats.
Spain's national statistics institute says there are 72,000 Argentines living legally in the European country.
River and Boca are the two most popular teams in Argentina, allegedly commanding between them 70 percent of the country's football fans.
They have won the Copa Libertadores nine times between them. While Boca have won the title twice as many times, River held it aloft most recently, in 2015.