An MMA fighter, Tim Hague, who was left in critical condition after being knocked out during a boxing match on Friday has died, his family has confirmed.

"It is with incredible sadness, sorrow and heartbreak to report that Tim has passed away today," Hague's sister, Jackie Neil said in a statement Sunday.

"He was surrounded by family, listening to his favourite songs. We will miss him so greatly."

Hague was taken to hospital in critical condition after being knocked out by Adam Braidwood in a fight at the Shaw Conference Centre on Friday. In a video from the match, Braidwood is seen knocking Hague down multiple times.

Hague, who fights out of Edmonton, Canada, also fought in the UFC. His nickname was "The Thrashing Machine" and he was cut from the UFC roster in 2011.

After his 2011 release, he wrote on his Facebook page that he needed time to heal from a concussion.

"I'm gonna take a little break away from MMA, let the brain heal from my concussion, and get the passion/fire back."

Hague's last fight before Friday's bout was in early April against Jared Kilkenny. He lost by TKO.

Hague trained at UFC Gym in Sherwood Park at least six times a week, said to the gym's owner, Alicia Landry. He usually stayed for two to three hours to lift weights and work on his conditioning. Though he boxed at another location, Hague offered one-on-one evening classes at Landry's gym.

"Locally, he's iconic," Landry said. "The MMA industry in Edmonton is very small and it's very tight knit. Everybody has each other's backs, regardless of past issues. He was probably one of the most positive people I've ever met," she said. "He was just happy to do whatever he could to help anybody — I've never seen him have a bad day. If he saw somebody struggling with pads, he'd step in and volunteer his time to set them on the right path."