We were talking to Mark about which hockey player would have the best shot at success in the UFC -- and without hesitation, Giordano brought up the legendary enforcer.

"I've never seen him lose a fight," Mark explained.

McGrattan -- 6'4", 235 lbs -- had a helluva fight record during his time in the NHL ... and is said to have not lost a single scrap during the 2013-2014 season despite playing in 76 games.

Here are some highlights. Enjoy the violence.