Former schoolteacher Jeff Horn stunned champion Manny Pacquiao to win the WBO world welterweight title with a unanimous points decision in Brisbane.

The three judges scored the fight 117-111, 115-113, 115-113 to the 29-year-old Australian at Lang Park.

"That's the decision of the judges. I respect that," said 38-year-old Pacquiao.

The Filipino, an eight-weight world champion, has now lost four of his past nine fights.

Horn, 29, was aggressive from the opening bell, although Pacquiao's left jabs scored points in the early stages.

Horn, who has now won 17 and drawn one of his 18 bouts, caused Pacquiao problems during the middle rounds and cut him above both eyes.

The veteran fought back with a brilliant counter-attack in the ninth round, only for Horn to win the 10th.

Both fighters tired in the final two rounds, with Horn's good work in the opening stages proving enough for a famous win.

Pacquiao was widely expected to dispose of Horn and set up a potential rematch with Floyd Mayweather but the 38-year-old struggled to cope with the aggression of his opponent, who immediately offered the Filipino a rematch in his post-fight interview.

Horn, fighting in front of a 50,000 strong partisan home support, shaded the opening round with his height and reach advantage before former eight-division world champion Pacquiao worked his way into the bout in the following two rounds.

The home fighter was caught by a solid left counter in the fourth which left him bleeding above the right eye as Pacquiao began to dominate the fight.

However, Horn responded well in the fifth before the two men accidentally clashed heads in the following round - leaving Pacquiao with a cut to his hairline, which hampered his vision for the remainder of the fight.

Horn moved ahead of the scorecards after slightly shading the seventh and eighth but was almost stopped in the ninth when Pacquiao landed a flurry of telling shots on the Australian.

The Queenslander showed great powers of recovery to keep attacking in the 10th, with both men exchanging blows in the final two rounds as the fight went to the scorecards.

Pacquiao's late dominance was not enough to sway the judges, although the Filipino fighter may feel aggrieved at the wide nature of the scorecards.

Very tough. I didn't expect that tough,' the 11-time world champion said. 'It's okay, it's part of the game. That's the decision of the judges, I respect that.'

Horn, meanwhile, has set his sights on fighting Floyd Mayweather, should Pacquiao turn down his offer of a rematch.

The Australian brandished a walking stick after being crowned champion and taunted the 40-year-old, who is set to come out of retirement to face UFC star Conor McGregor later this year.

'This is no joke, which one does he want? The walking stick or the gloves?' Horn said.