Boca Juniors coach Gustavo Alfaro and forward Ramón Ábila accused River Plate players of diving following a 2-0 Copa Libertadores semi-final, first leg loss.
Colombian Rafael Borré opened the scoring on seven minutes from the penalty spot after he was fouled in the area by Emmanuel áas. Ignacio Fernández clinched the victory 20 minutes from time on Tuesday at River's Monumental stadium.
The penalty was awarded by Brazilian referee Raphael Claus following a VAR review.
"No-one was appealing for a penalty. They [the video assistant referees] called him and he reviewed it," complained Ábila.
"It seems like they've got a lot of telephone credit because they kept calling him," added the Boca forward, whose teammate Nicolás Capaldo was sent off for an injury time foul following another VAR review.
It was the perceived diving that most irked Abila.
"We know that [River forwards] Borré, [Exequiel] Palacios and [Nicolás] De La Cruz practise simulating fouls," he said. "In every round, River get a penalty. We knew what we were up against."
Alfaro concurred, even going so far as to reveal he had shown his players "a video of the number of situations in which River look for a penalty. They're always diving."
Incensed Boca players surrounded Claus both after the penalty award and at the final whistle.
The VAR controversies were the only ones, though, in a match that could easily have proved more combustible.
It was a repeat of last year's final, whose second leg was twice postponed before being played two weeks late and 10,000 kilometers away in Madrid after Boca refused to take the field after their team bus came under attack from River fans on the way to the stadium.
Two Xeneize players required hospital treatment while others suffered effects from inhaling pepper spray fired by police to disperse River fans.
Boca failed in appeals to South American football's governing body CONMEBOL and the Court of Arbitration for Sport to have the trophy awarded to them without playing.
Having drawn the home leg 2-2, they lost 3-1 after extra time in Madrid as River claimed a fourth Libertadores triumph.
The winners following the second leg at Boca's iconic Bombonera stadium in three weeks time will face Brazilians Grêmio or Flamengo in the November final.