ALEXANDER VOLKANOVSKI defeated Chan Sung Jung in a technical knockout to retain his featherweight title at UFC 273.
With the victory over Jung (also known as the Korean Zombie), Volkanovski, 33, extended his professional winning streak at 21.
Jung was left with severe breathing difficulties after three rounds.
Between rounds, he was unable to sit up on his stool and was prone to slumping against the octagon.
Jung was examined by the cageside doctor before the fourth round began. Jung said he wanted to continue.
Referee Herb Dean stopped it 45 seconds into the fourth round of the five championship rounds.
READ MORE ABOUT UFC
Later, Jung was praised for Dean's intervention and for his help in preventing further damage.
The champion and the challenger had a long, intimate hug in the octagon. The Korean Zombie seemed to be crying as he knelt down on the mat.
Volkanovski has won 11 of his previous fights. He said that he had told him all week before the fight that he was on another level.
"I can't stop, and I just showed him. He took much more than I expected.
Get a PS10 Bonus with 100s of Games to Play and No Deposit Required"I felt they could have stopped it earlier, and I began feeling bad in there. But that's the sport that we're in."
Jung, 35, stated that he had now considered retiring after the fight.
Jung stated: "I was the most confident of all my career.
"I was not tired, and I was ready for the challenge but it felt like I had hit a wall that I couldn't get over.
"After every loss I think about leaving the Octagon or this MMA game, but I will need to take more time to reflect on it and decide if I will continue fighting. That will be something I have to consider."
