Boca Juniors have confirmed the news that striker Dario Benedetto has ruptured the anterior cruciate ligament in his right knee.
The Argentina international will have surgery in Buenos Aires on Thursday and faces a battle to play again this season and in next year's World Cup.
Benedetto got hurt during the second half of his team's 2-1 home league defeat against Racing Club on Sunday night.
With nine minutes remaining, he appeared to twist his right knee while waiting for the ball in the Racing area and was carted off the pitch.
Three minutes earlier, Benedetto escaped a red card for a harsh challenge on Racing midfielder Augusto Solari, with the referee showing him a yellow card instead.
Tests done after the game confirmed the worst prognosis, with the Superliga's leading scorer expected to be sidelined for a minimum of six months, a serious blow for league leaders Boca.
The 27-year-old, who played in Argentina's last three World Cup qualifiers, starting in the last two, spoke after the news was confirmed and has vowed to come back stronger.
Benedetto, who scored his ninth league goal of the season on Sunday, told TYC Sports: "I knew immediately that something was wrong and I knew it wasn't a sprain as I've suffered one in the past.
"These are things that happen in our profession.
"Now I have to stand strong, face the surgery and give my all in the recovery process.
"The World Cup? Right now it's the least of my concerns. My only focus is to recover in order to return to the pitch as soon as possible."