Colombia manager Jose Pekerman dedicated his side's crucial 3-0 win over Poland on Sunday to midfielder Carlos Sanchez after reports the midfielder received death threats for his red card against Japan.
Sanchez has had "a very hard time" dealing with the fallout from his third-minute sending-off in the 2-1 defeat to Japan in Colombia's opening game, Pekerman said.
He said he spoke for the whole squad when he dedicated Colombia's win over Poland to the 32-year-old player.
"This victory is dedicated to Carlos Sanchez, because he's had a very hard time in the past days. I want, and we want, to share it with him," he said.
Pekerman added: "We received certain information, but I can't confirm anything. The player was deeply affected by this matter.
"It went beyond football. It's a game that we play with a lot of hard work and dedication, but these things should not be taken lightly.
"Whether it's confirmed or not... this is extremely painful."
Read more on World Cup 2018:
World Cup 2018: Day 10 updates - Belgium hammer Tunisia 5-2
It evoked memories of the chilling murder of Colombia player Andres Escobar, who was killed after his own goal led to defeat to the United States in the 1994 World Cup and Colombia's elimination from the tournament.
Robert Lewandowski's Poland were unceremoniously dumped out following the loss to Colombia, who can guarantee a place in the last 16 by beating Senegal in their concluding game in Group H.
The West Africans and Japan are both in control of their destiny following a 2-2 draw in Yekaterinburg that left both nations on four points.