A martial arts fighter suffered a significant brain injury during a bout in Minneapolis over the weekend, underwent emergency surgery and is said to have "a very long road to recovery."

Nate Kosberg, 26, who trains out of the Academy gym in Brooklyn Center, was injured during his amateur Muay Thai bout Saturday at the Varsity Theater in Minneapolis and was in serious condition Thursday at HCMC.

The 137-pound Kosberg, who lost the fight in a decision, "didn't appear hurt at all … after the fight and was talking and laughing," said Kaitlin Young, a fellow fighter who helped put together the 14-bout card.

Once outside the ring and while taking off his gear, "he started to pass out," said Young, who was ringside during Kosberg's bout.

An ambulance hired by the promoter to be at the venue in case of such an emergency raced Kosberg the few miles from Dinkytown to HCMC in downtown Minneapolis for what Young described as a life-threatening cerebral hemorrhage, and Kosberg underwent surgery to remove a blood clot.

Kosberg "has a very long road to recovery but is thankfully still with us," Young said in a posting on a fundraising web page set up on the fighter's behalf.

Muay Thai, or Thai boxing, uses stand-up striking with fists and feet along with various clinching techniques. Bouts are held around the world, and some online videos have drawn millions of views each.

Kosberg's bout of three two-minute rounds and the rest of the card had a doctor ringside, and the fights were sanctioned by the Iowa-based Thai Boxing Association-Sanctioning Authority, Young said.

Minnesota's Office of Combative Sports, which sanctions boxing and some other forms of organized fighting in the state, does not sanction Muay Thai and did not oversee this card, said agency spokesman James Honerman.

Away from the ring, Kosberg just ended his time on staff at Windom Dual Immersion School in south Minneapolis as a physical education teacher in order to concentrate more fully on his fighting career, said school district spokeswoman Julie Brown. He joined the district in January 2016 as an associate educator before becoming a teacher in September of that year.

He's also been teaching at A Work of Art boxing and fitness gym in Minnetonka, Young said.

The Minneapolis South High School graduate received a child psychology degree from the University of Minnesota and also minored in Spanish, according to his Windom school biography page.