Fluminense's former Brazil international Marcelo was reduced to tears as he received a red card for a devastating tackle on Argentinos Jrs defender Luciano Sanchez, resulting in a horrifying injury on Tuesday.
The incident unfolded as Marcelo was skillfully dribbling past Sanchez.
However, in a split second, disaster struck when his leading foot missed the ball and collided with the Argentine's shin with immense force.
The impact was so severe that Sanchez's leg buckled underneath him, contorting at a shocking angle, leaving him writhing in excruciating pain on the pitch.
The gravity of the injury was evident as Sanchez had to be rushed to a nearby medical clinic for urgent treatment.
The diagnosis was grim, with Argentinos confirming on the messaging platform X (formerly known as Twitter) that he had suffered a dislocated left knee.
The distressing scene left players and spectators alike in stunned silence, a stark reminder of the inherent risks in the beautiful game.
Overwhelmed with guilt and remorse, Marcelo took to Instagram to express his sorrow for the unfortunate incident.
"Today, I had a very difficult moment on the pitch. I unintentionally injured a fellow player. I want to wish him the best possible recovery. All the strength in the world," he said.
Fluminense FC, Marcelo's Brazilian club, also extended their support and well-wishes to Sanchez through a compassionate post on social media.
"Fluminense FC expresses its solidarity and wishes a speedy recovery to Argentinos Juniors defender Luciano Sanchez, who was injured in an accidental move in tonight's match," they stated, illustrating the sportsmanship and camaraderie that prevail even amid such distressing events.
The intensity of the match was further evident in the 1-1 draw in the first leg of the round of 16 clash, which took place at the historic Diego Armando Maradona stadium.
However, the spectacle was overshadowed by the unfortunate turn of events and the harrowing injury that left everyone united in their concern for the injured defender.