Manny Pacquiao lost his WBO welterweight world title to Jeff Horn in a stunning, unanimous points decision in a Sunday afternoon bout billed as the Battle of Brisbane in front of more than 51,000 people.

The 11-time world champion entered the fight at Suncorp Stadium as a hot favorite but got more than he bargained for against the 29-year-old former schoolteacher.

Still, Pacquiao dominated the later rounds and had Horn wobbling at the end of the 9th.

"I felt buzzed for sure, but I'm the Hornet — I've got to come back," Horn said of that round. "I'm not a quitter. Australians aren't quitters to start with. We've showed we're winners.

"It was the battle of Brisbane, that's for sure. Absolutely unbelievable. So pumped."

​Pacquiao's long-time trainer Freddie Roach predicted the fight would be short and sweet but Horn — unbeaten in his 17 previous professional fights — applied pressure by winning some of the early rounds and Pacquiao needed treatment during the 6th and 7th rounds for a cut on the top of his head that resulted from a clash of heads.

The judges scored the fight 117-111, 115-113 and 115-113, and Horn declared himself "no joke."

Roach had said earlier in the week that he'd think about advising Pacquiao to retire if he lost the fight, but that would depend on how he fought.

Horn can't see Pacquiao retiring any time soon.

"I'm sure he'll want to come back. It was a close decision and I'm sure he'll want to come back and prove himself," Horn said.

Top Rank promotor Bob Arum said there was a clause for a rematch, but he'd give it time before talking to Pacquiao about it.

"I know Jeff would welcome the rematch, but I don't know Manny's future position," Arum said. "Is he going to stay in politics and not continue in boxing? I don't know, and he doesn't know now — it's unfair to ask him now."

Pacquiao's camp had talked about a rematch with Mayweather if he got past Horn, hoping to avenge his loss on points in the 2015 mega fight. That seems to be a distant chance now.

Pacquiao, who entered the fight with a record of 59-6-2, 38 knockouts, was defending the WBO title he won on points against Jessie Vargas last November.