FILIPINO star Manny Pacquiao has failed to retain his World Boxing Organization welterweight title after losing to Australian challenger Jeff Horn via unanimous decision on Sunday.

The fight, dubbed the ‘Battle of Brisbane’ was held at the Suncorp Stadium in Brisbane, Queensland, Australia.

In the first round, both fighters felt each other out with Horn initiating the attacks, but Pacquiao kept calm and laughed off the shots. Towards the end of the round, Pacquiao landed some quick counter attacks himself.

Round two saw Horn coming in hard on Pacquiao, showing that he meant business.

The battle went on until the sixth round where Pacquiao suffered some bleeding on his forehead due to an accidental head butt. Horn then had Pacquiao cornered, landing him a damaging uppercut.

Another head butt occurred in the seventh round, and Pacquiao suffered another cut on his forehead.

Pacquiao displayed aggressiveness in ninth round, showing no mercy to his opponent. But Horn didn’t back down either, proving his worthiness throughout the other remaining rounds.

Both warriors gave everything they had, but the final decision went to Horn with a score of 117-111, 115-113, 115-113.

Meanwhile, in a post fight interview, both Pacquiao and Horn said they would be open for a rematch.

This was Pacquiao's first fight since his unanimous decision win for the title over American Jessie Vargas in Las Vegas last November.

Pacquiao won the WBO title for the first time in 2010 when he beat Puerto Rican boxer Miguel Cotto.

He lost the belt two years later to Bradley, but then got it back by winning the rematch with Bradley in 2014.

Pacquiao then lost in 2015 to American boxer Floyd Mayweather.