UFC middleweight champion Dricus du Plessis submitted former champion Israel Adesanya in the fourth round to retain his title at UFC 305 in Perth, Australia on Sunday.
Back-to-back right hooks knocked down a retreating Adesanya, with Du Plessis taking him back and sinking in the rear-naked choke.
Adesanya tapped, stopping the bout three minutes and 38 seconds into the five-minute round.
It was the first time Nigerian-New Zealander Adesanya was submitted in his professional MMA career, which stands at 24 wins and four losses. South Africa's Du Plessis, who has won all eight of his fights since joining the UFC, progressed to 21-2.
"I always knew if I'm in trouble fighting one of the, if not the best strikers ever in this division, I need that takedown," Du Plessis said after his first title defence since winning the belt in January.
"This man is the king of getting back up. No one can take him down and keep him there."
Du Plessis had taken Adesanya down in the second round and attempted to choke him, but the challenger got back up and ripped into Du Plessis with kicks and punches to the body in the third round.
"Believe me, I do not want to get kicked by that man again," Du Plessis said. "Izzy, if you decide to retire tonight, thank you."
Adesanya, who has now lost three of his last four fights, said he intended to keep going.
"I just made a stupid, dumb mistake," he said. "I'm 35, I'm doing the right things... watch this, I'm not leaving.
