Philadelphia Union beat Saprissa 1-0 in their Concacaf Champions League last 16 first leg tie on Wednesday evening.
The MLS outfit prevailed courtesy of Kacper Przybylko's 34th minute goal.
The game was marred by a quite brutal challenge that occurred in the dying moments of the game.
Philadelphia's Kai Wagner blocked a cross and was then first to the loose ball.
But, despite not looking like he had any real chance to get the ball, Ricardo Blanco came charging in and completely wiped out his opponent.
Wagner went flying before crashing to the ground.
The MLS side were understandably not very happy and a mass brawl broke out between the two sides.
Fortunately, Wagner did not sustain a serious injury and was able to continue.
It was a crazy challenge and you can watch the moment below:
And view a close up angle below:
Incredibly, the referee decided that wasn't even a red card offence.
Blanco was shown a yellow card for his challenge.
Saprissa's Daniel Colindres and Michael Barrantes were booked, while Philadelphia's Gregory Monteiro and Jakob Glesnes were also cautioned.
Football fans on Reddit couldn't believe Blanco wasn't given his marching orders.
"How was that not a red? That referee needs to find a new line of work what an embarrassment,"
Mcm_xci said: "If there was a card beyond red, this would be deserving of it. But yes sure, yellow it is."
"That is genuinely one of the worst challenges I have ever seen," another fan wrote.
While Naval107 said: "Ban the player for life. He purposely just tried to end someone's career."
The second leg between the two sides takes place next week. Given how the first leg ended, the game in the United States promises to be a tasty affair.