JACKSONVILLE, Fla. (AP) — Alexander Volkanovski mauled Chan Sung Jung at UFC 273 early Sunday, earning a technical knockout seconds into the fourth round to retain the featherweight belt.

The 33-year-old Volkanovski (24-1) extended his professional winning streak to 21, including an 11-0 mark in UFC competition.

Jung, better known as the Korean Zombie, was battered, bloodied and struggling to breathe after the first three rounds. He insisted he wanted to keep going, but the referee stopped the bout 45 seconds into the fourth of five championship rounds.

“Too (expletive) good,” Volkanovski shouted inside the octagon after his latest victory.

“Alexander the Great” delivered most of the blows in a fight that looked like it might end much earlier than it actually did. Volkanovski’s last four fights went the distance. But he was considerably quicker than Jung, essentially putting on a clinic in mixed martial arts.

“I’m on another level right now and I can’t be stopped,” Volkanovski said, adding he was hoping the ref would halt the fight sooner and that he felt bad for Jung in the final minutes.

“It felt like I hit a wall that I could not go over,” said Jung, who was making his first title bout since 2013. He went 3,171 days between shots at the featherweight belt.

The 35-year-old Jung dropped to the mat after the fight was called and later indicated through an interpreter that he might consider retirement.

The main event was the most lopsided on UFC 273’s main card.

Aljamain Sterling became the undisputed bantamweight champion by defending his belt against Petr Yan. They were involved in a controversial disqualification a little more than a year ago. Yan was DQ’d for an illegal knee after dominating the fight.

Sterling (21-3) looked like a different fighter in this one, controlling Yan on the mat for nearly eight minutes in the second and third rounds. Yan (16-3) battled back in the final two rounds, doing enough to get a split decision.

“I think I won this fight and I got robbed,” Yan said. “I want a rematch.”

Sterling had no plans for a trilogy fight with Yan, instead calling out former bantamweight champ T.J. Dillashaw for his next bout.

UFC’s third trip to Jacksonville in three years drew a packed house that included Florida Gov. Ron DeSantis, former UFC heavyweight champion Andrei Arlovski, Las Vegas Raiders defensive end Maxx Crosby, Jaguars minority owner Tony Khan and legendary wrestling announcer Jim Ross.

They were treated to an epic event.

Not only did they get two title fights to close out the night, but they witnessed arguably the best bout of the year. Sweden’s Khamzat Chimaev took another step toward mixed martial arts stardom with a unanimous decision against 35-year-old Brazilian Gilbert Burns in the welterweight division.

Chimaev and Burns went to toe-to-toe for three rounds, exchanging punches and raising their profiles. It was Chimaev’s most impressive outing to date and proved he’s a potential championship contender.

Chimaev (11-0) remained undefeated and answered any lingering questions about how good he could be by taking down the second-ranked Burns (20-5).

“I didn’t know he was so tough,” Chimaev said.

Chimaev hadn’t gone to a third round in any of his previous professional fights. He was gassed and gashed by the final round in this one, his first against a ranked opponent.

“This is what I was waiting for,” said Chimaev, a sizable cut under his left eye. “I’m in pain, bloody and tired.”

Other fights on the main card:

— Mackenzie Dern (12-2) used a split decision against Tecia Torres to win for the fifth time in her last six fights. With her husband and young daughter sitting cage side, Dern dominated the second round thanks to a variety of Brazilian jiu-jitsu moves. But the 32-year-old Torres (13-6) escaped two submission holds and was impressive over the final five minutes to nearly upset the fifth-ranked woman in the strawweight division.

— Three-time Olympian Mark Madsen (12-0) remained undefeated with a unanimous decision over 39-year-old Vinc Pichel (14-3) in the lightweight division. Madsen won a silver medal for Denmark in the 2016 Olympic Games in Brazil.