The South American nation has been rapt in the days leading up to the event as the game between two of football's most bitter opponents dominates conversations and media coverage.
"There's never been a final like this in 58 years (of the competition)," Alejandro Dominguez, president of the South American football confederation (CONMEBOL), said on Friday.
It is the first time Argentina's two biggest clubs have met in the final of the region's premier club competition, South America's equivalent of Europe's Champions League.
But a rivalry that is as famous for the passion shown by fans as for the skill of the players is also causing concern.
Argentine football has been tarnished by violence in recent years and only home fans will be able to attend each leg in keeping with a ban on away supporters introduced five years ago.
The last time the teams met in the Libertadores in 2015 Boca fans attacked River players with pepper spray at halftime and the referee called off the match with Boca kicked out of the competition.
Football is a passion in Argentina, the home of national team greats such as Diego Maradona and Lionel Messi, and the presidents of the two clubs met with Dominguez on Friday to plead for peace and a focus only on football.
Adding to the excitement is the fact that this year's final is the last to played on a home-and-away basis before CONMEBOL adopts a single-match format in 2019.
Even the players admit the fanatical build-up to the match has taken its toll.
"There is little to enjoy and I'm not enjoying it," Boca Juniors captain Pablo Perez told reporters in Buenos Aires ahead of the first leg at Boca's Bombonera stadium.
"I am trying to treat it as a World Cup final and think about it all the time so that no details escape me," he added.
The second leg will be at River's Monumental stadium in two weeks' time.
(Reporting by Ramiro Scandolo, Writing by Andrew Downie; editing by Bill Berkrot and Ken Ferris)
