It's all to play for at the Monumental in two weeks time.
In a thrilling Superclásico, River Plate twice came from behind to snatch a 2-2 draw with fierce rivals Boca Juniors in the first leg of their weather-delayed Copa Libertadores final on Sunday.
A last-minute save from River goalkeeper Franco Armani to deny Boca striker Dario Benedetto left the Sclash finely balanced heading into the second leg in the capital on November 24.
Boca twice took the the lead through goals from Ramón Ábila and Benedetto, only to see River fight back through strikes from Lucas Pratto and an own goal from Carlos Izquierdoz.
Home fans flooded into the Bombonera for the clash. The game at Boca's famous stadium had been shifted to Sunday after torrential rain forced a postponement on Saturday.
Ramon Abila opened the scoring in the 34th minute at La Bombonera Stadium with a powerful left-footed shot into the top left corner. But the lead didn't last long: Pratto equalised two minutes later, sending the ball into the bottom left corner.
Benedetto made it 2-1 to Boca with a header in first-half stoppage time before Boca defender Carlos Izquierdoz scored an own-goal in the 61st minute, attempting to defend a ball into the box.
The eagerly anticipated final marked the first time in the 58-year history of the Copa Libertadores that River and Boca, Argentina's fiercest rivals, had met in the final.
With Boca's famed La Bombonera stadium rocking with excitement, however, it was River who were the quicker to settle.
The visitors threatened to take an early lead when Gonzalo Martínez's curling free-kick was clawed wide for a corner by Boca goalkeeper Agustín Rossi.
River almost scored from the ensuing corner, but Lucas Martínez directed his header wide wastefully to leave La Bombonera breathing a collective sigh of relief.
River continued to enjoy the better of the early chances, and again threatened the Boca goal after 16 minutes when Rafael Borre's glancing header was brilliantly pushed around the post by Rossi for a corner.
However after soaking up the early River pressure, it was Boca who made the breakthrough on 34 minutes with their first shot of the game.
Ábila forced a desperate save from Armani with a fierce right-foot strike, but the River goalkeeper's block fell back into the path of the Boca forward who smashed an angled left-foot shot through a gap at the near post.
His opener had the massed yanks of blue-and-yellow clad fans bouncing in delirium but their joy was short-lived as River snatched an equaliser immediately.
Gonzalo Martínez threaded a perfectly weighted pass through to Pratto, and the Argentine international drilled a low finish across the diving Rossi which crept in off the far post.
River almost took the lead four minutes later when Gonzalo Martínez's shot cannoned off Rossi's legs in the Boca goal.
Instead though it was Boca who regained the lead on the stroke of half-time, with Benedetto glancing in Sebastián Villa's floated free-kick.
River however fought back gamely in the second half and equalised in the 61st minute when Gonzalo Martinez's teasing free-kick caused panic in the Boca area.
Izquierdoz, who had been marking Pratto, leapt to clear but succeeded only in steering the ball past Rossi in the Boca goal for 2-2.
With time running out, Boca then missed a glorious chance when Carlos Tevez broke into the area.
The veteran striker calmly squared to the unmarked Benedetto eight yards from goal, but the forward shot straight at Armani who saved to preserve River's draw.
"Both teams had a good game and the result was fair for both," Benedetto said. "I think Boca's football was better but River also had its merits."
He called the 2-2 draw "a fair result."
River's star player played tribute to Boca's shotstopper Rossi.
"The Boca goalkeeper had two or three spectacular saves ... we were shooting at goal well but he was saving some very good shots," said Pratto, who was chosen as man of the match.
All eyes now turn to the second-leg showdown, due to take place in just two week's time. The two rivals will face off at the Monumental, River's home ground, on Saturday, November 24 (kick off 5pm local time).
"This will be settled at the Monumental," Pratto said. "It will be 'Kill or be killed.'"
The match in stats
Copa Libertadores 2018 - Final - First leg
Stadium: La Bombonera (Buenos Aires)
Referee: Roberto Tobar (CHI)
Boca Juniors: Ábila (33 minutes), Benedetto (45 + 1)
River Plate: Pratto (35), Izquierdoz (own goal) (60)
Boca Juniors: Jara (37), Villa (43), Abila (48), Tevez (90 + 5)
River Plate: Casco (67), Borré (75)
Boca Juniors: Agustín Rossi - Carlos Izquierdoz, Lisandro Magallán, Lucas Olaza, Leonardo Jara (Julio Buffarini 83) - Wilmar Barrios, Pablo Pérez, Nahitán Nández - Ramón Abila, Cristian Pavon (Darío Benedetto 27), Sebastián Villa (Carlos Tevez 73).
River Plate: Franco Armani - Javier Horacio Pinola, Lucas Martinez Quarta (Juan Quintero 77), Jonatan Maidana, Milton Casco, Gonzalo Montiel - Enzo Pérez (Bruno Zuculini 75), Gonzalo Martínez (Ignacio Fernández 58), Exequiel Palacios - Lucas Pratto, Rafael Santos Borré.