Manny Pacquiao lost his slice of the world welterweight championship tonight when he lost a unanimous but controversial decision to little-known Australian Jeff Horn in Brisbane.

The fight happened on Sunday morning, in Australia, so that it could be shown on live non-pay-per-view TV in the U.S., where it was Saturday night.

(Here is video of the whole of the fight.)

Most observers who adjudge themselves experts thought the Filipino won an often awkward fight, one that seemed to produce a clash of heads at least once in every round.

Pacquaio left the door open to the judges going against him by failing to knock out — or knock down — the former schoolteacher from Queensland, and the judges certainly would have felt the yearning of the crowd, made up primarily of Horn fans.

This is the sort of thing that happens late in the careers of little guys who have climbed a weight category — or seven, as Pacquiao has — during their careers.

They still can land punches, but they have trouble knocking out men who are bigger than they are.

The good news, for Paquiao’s millions of fans?

A rematch is almost certain. Pacquiao can demand one and is expected to, though his trainer, Freddie Roach, suggested he might tell the 38-year-old fighter/politician that it is time to give up getting hit in the face as a way to make a living.

The number of boxers who make that decision and stick to it … not many. Usually, they continue to fight until no one is willing to pay to see them.

A rematch, especially if it is held in Australia, likely will generate a similar size gate — in excess of 55,000.

Pacquaio’s best chance for getting out of town with the belt he took into the ring was in the ninth round, when he staggered Horn several times. The Aussie looked like he was just hanging on, the final 90 seconds of the round.

Moments after he got to the end, the referee came to Horn’s corner and told him, “If you don’t show me something I’m going to end this fight.”

Horn responded immediately in Round 10, perhaps from a deep well of toughness, perhaps because Pacquaio might have been arm-weary from all the punches he threw in the previous round, allowing Horn some space to breathe and get himself back in the fight.

Pacquaio’s record fell to 59-7-2 with 38 knockouts — but no knockouts in 13 fights since he KO’d Miguel Cotto in 2009.

He did not seem overtly aggrieved at the judges’ decision, perhaps because he reportedly was guaranteed $10 million compared to Horn’s $500,000.

It was an entertaining bout, at the least. Horn pressed ahead most of the time, and Pacquiao rarely retreated. Horn seemed happy to tie up Pacquiao as often as possible, and the latter often made that possible by ducking his head under Horn’s right arm.

Horn, 29, improved to 17-0-1 with 11 knockouts.