River Plate will host the second leg on 24 November
River Plate twice came from behind to earn a 2-2 draw with Argentina rivals Boca Juniors in Sunday's first leg of the Copa Libertadores final.
The tie had initially been due to take place on Saturday but was postponed because of heavy rain.
Ramon Abila put Boca ahead in the first half before Lucas Pratto equalised.
Dario Benedetto restored Boca's lead just before the interval but Carlos Izquierdoz put through his own goal to ensure the game ended all square.
The second leg of the final will take place at River's Monumental stadium on 24 November.
Sunday's encounter marked the first time in the 58-year history of the Copa Libertadores that River and Boca - who have one of the fiercest club rivals in world football - had met in the final.
Away fans were banned from attending the game because of safety concerns but Boca fans had La Bombonera stadium rocking all on their own.
However, despite the absence of their fans, River settled better than their opponents and they are level going into the second leg, which will be played in front of their own fans.
No away supporters will attend either tie with the threat of violence high. Boca fans provided a raucous atmosphere on their own
The game had been due to take place on Saturday but was postponed because of heavy rain
There were a reported 51,000 spectators at Sunday's game
The fiercest rivalry in football?
The Buenos Aires derby is one of Argentina's fiercest rivalries - and rarely disappoints.
Here are some memorable moments from previous typically feisty encounters.
Sometimes the players need more than shin pads for protection. In this 2015 game at Boca's legendary La Bombonera stadium, River Plate players made a swift exit via a tunnel of police riot shields after home fans directed pepper spray at them and the game was suspended
When pigs fly... This is the kind of thing you see at a Superclasico. This inflatable Boca Juniors pig was flown during a draw with River Plate in 2012. How did they even get this in the ground?
No paparazzi please! Boca Juniors players mocked their rivals last year by hiding under a white sheet after securing the 2016-17 Argentine Primera Division title
A plastic chicken tied to the fence at La Bombonera may seem insignificant, but 'The Chickens' is a nickname Boca have taunted River Plate with since 1966, when they lost 4-2 to their rivals having been 2-0 up
Defeat in the Superclasico can leave supporters literally climbing the walls - as Boca fans demonstrate after losing 3-1 last year - and the losing manager, on this occasion Guillermo Barros Schelotto, disconsolate
Two red cards, riot police and a goal after 45 seconds... it's just a typical Superclasico. And after all of that, like this game in 2013, it could end in a draw
Can you come with us please? Boca midfielder Fernando Gago had to be escorted off the pitch by riot police in one of 2014's games after getting a straight red card
Fireworks are guaranteed in this fixture... River Plate fans lit the way at the 2017 Supercopa Argentina final against Boca, which they won 2-0. It was their first Supercopa Argentina title
Anything you can do... A Boca fan sets off a colour-co-ordinated firework. His side have won 33 Argentine Primera Division titles - three fewer than River Plate
Let's finish how we started - with a riot shield. River Plate boss Marcelo Gallardo needs maximum security even before matches at Boca Juniors