Isaac Johnson, MMA fighter, collapses and dies during match in Chicago: Check cause of death as probe continues

A shocking incident occurred in Chicago, where 31-year-old MMA fighter Isaac Johnson died after sustaining injuries during a match in the city, according to reports.

Things took a drastic turn after Johnson collapsed due to the injury suffered during the third and final round of his match against fighter Mario Aleksandrovski at the Matador Fighter Challenge at Cicero Stadium on Friday, November 21, 2025, according to NBC 5 Chicago and Fox 5 Washington, DC.

A town spokesperson told NBC 5 Chicago that an ambulance was called at 8:38 p.m. local time to transport “an injured fighter” to the hospital. Multiple reports claimed that Johnson later died at 12:01 a.m. at the Loyola University Medical Center, the outlets reported. Also, this was reportedly Johnson's first Thai boxing match.

Autopsy to reveal cause of death

The Cook County Medical Examiner's Office (CCMEO) said an autopsy has been scheduled to determine the cause of death, according to reports.

The Illinois Department of Financial and Professional Regulations (IDFPR) is investigating the incident, Fox 5 Washington, D.C. reported. PEOPLE has reached out to the CCMEO and IDFPR for comment.

What is the Matador Fighter Challenge?

The Matador Fighter Challenge is described as an “action-packed showdown” that “brings you the ultimate MMA and Thai event, where local warriors will battle it out in high-stakes, high-intensity matches,” according to its website.

Joe Goytia, the promoter of the event, said that Johnson passed the physical required by the state before his match, per Fox 5 Washington, D.C.

“This is a post I hoped to never make. Last night, one of the fighters in our event, Isaac Johnson, collapsed towards the end of his fight. Medical attention was given by medical staff on hand and he was transported to hospital. I was then informed at around 1:30 a.m. this morning that he didn't make it,” Goytia wrote on Facebook after Johnson’s death.

“I don't have the words to express how I feel right now, all I can say is my deepest condolences to his family, friends, and teammates. We will know more as the medical report is released,” he added.