The Australian southpaw dominated a game but outclassed Brandon Glanton throughout Zuffa Boxing’s 12-round main event at Meta Apex, UFC’s performance complex in Las Vegas. Opetaia shut out Glanton on all three scorecards — 119-106 apiece, according to judges Eric Cheek, Patricia Morse Jarman and David Sutherland.

Opetaia, who was a 20-1 favorite according to DraftKings, improved to 30-0. Atlanta’s Glanton (21-4, 18 KOs) didn’t win a round, but he displayed plenty of toughness in taking a variety of power punches without going down.

“My coach isn’t happy,” Opetaia told Max Kellerman during his post-fight interview. “It was all right. I knew Brandon was gonna bring it. I knew it was gonna be a hard fight and I knew he was tough as nails.”

Opetaia, 30, defended his Ring cruiserweight title and won the first Zuffa Boxing belt awarded in any division. The IBF declined to sanction Opetaia-Glanton as a title fight late Friday night, just a couple hours after their final press conference at nearby MGM Grand.

The IBF indicated in its statement that it would strip Opetaia of its title for the second time if he fought for the Zuffa Boxing belt. He was still listed as a champion Sunday night on the IBF’s website.

Glanton, 34, entered their bout ranked 10th by The Ring and 15th by the IBF.

Glanton’s courage was commendable against a superior opponent, but he suffered his most lopsided loss in 25 professional fights. His prior defeats came by unanimous decision to former WBO champ Chris Billam-Smith, majority decision to Soslan Asbarov and split decision to David Light.

Opetaia finally seemed to hurt Glanton when his left hand made the courageous challenger stumble backward with 50 seconds to go in the 12th round. Glanton managed to make it to the final bell, despite his face being bloodied and swollen.

Referee Allen Huggins took a point from Opetaia for holding at 2:21 of the 11th round. Huggins previously deducted two points from Glanton, one for holding and another for a low blow.

A right uppercut by Opetaia snapped back Glanton’s head with about 1:50 to go in the 10th. Approximately 50 seconds later, Glanton blasted Opetaia with a right.

Opetaia continued to win on the inside during the ninth round. He landed left uppercuts, straight lefts and right hooks to build on his big lead.

A second low blow by Glanton sent Opetaia to one knee and cost him another point, a second such deduction with 2:21 to go in the eighth.

A sharp Opetaia picked apart Glanton on the inside with head and body shots throughout the seventh round.

Huggins deducted a point from Glanton for holding with exactly one minute to go in the sixth. Glanton wasn’t warned before the point deduction and didn’t appear to excessively hold prior to having a point taken away.

Glanton’s right landed below Opetaia’s belt and sent him to one knee with eight seconds remaining in the fifth. Huggins gave Opetaia time to recover and warned Glanton for the low blow.

Opetaia’s precise combination punching got Glanton’s attention just before the midway mark of the fourth round. He landed a left uppercut, three straight right hooks and a right uppercut that made him cover up.

Opetaia’s straight left landed flush with 25 seconds to go in the third, when swelling formed in the middle of Glanton’s forehead. Opetaia’s thudding right to the body temporarily slowed down Glanton.

Glanton tried his best to cut off the ring the second round. Opetaia fought from a comfortable distance, though, and consistently landed punches as Glanton bent over and pressed forward.