Horn beat Pacquiao in the WBO welterweight crown in Brisbane on Sunday, awarded the unanimous wins on points.
The decision has prompted debate on social media and among commentators, with some even suggesting the outcome was rigged.
Judges Waleksa Roldan (117-111), Chris Flores (115-113) and Ramon Cerdan (115-113) adjudicated the fight. Roldan and Flores are from the United States and Cerdan is from Argentina, yet there have been accusations it was a hometown decision.
Former schoolteacher Horn says he believes he won fair and square.
"There's always going to be the backlash where people will say I got lucky or whatever, there's always going to be the naysayers saying I didn't win the fight," he said.
"But I felt like I won the fight. I think a lot of Queenslanders think I won the fight and people around the world. So you will always have the select few that will be against you."
Pacquiao, whose defeat was his first since his blockbuster clash with Floyd Mayweather Jr in 2005, indicated on Sunday that he would take up the option of a rematch and Horn said he would be delighted to face the 38-year-old in his first title defence.
"I'm happy to have a rematch, it'd be good to have him back here fighting," he added.
Horn said he was prepared for the media attention becoming a world champion would bring, and hoped his victory would trigger a renaissance in Australian boxing.
"It puts Australian boxing on the map, it's what we've needed for a long time, it's kind of died a bit in the past but hopefully this will invigorate it," he said.
Brisbane set to host Horn's title defence
Brisbane is firming as the likely destination for Jeff Horn's first WBO welterweight title defence, but when it will happen or who he will fight remains entirely up in the air.
Everything hinges on whether the Filipino great wants to continue boxing after his contentious points defeat to Horn in Sunday's 'Battle of Brisbane'.
Pacquiao, 38, has a rematch clause in his favour and said in the ring after suffering his seventh career loss he would be happy to activate it.
Queensland Premier Annastacia Palaszczuk said: "If there's going to be a rematch in Australia, it's going to be here in Queensland on my watch."
Lonergan said he had received advice not to schedule a fight at Suncorp in November, the shadow date for Horn-Pacquiao II, because of the higher chance of rain.
"You definitely don't want it to be raining but we'll have a talk to everyone and see if we can find a date that works. Manny's got to make decisions first," he said.
Horn's deal with Duco and Bob Arum's Top Rank stipulates they will control his next two fights.
Arum, boxing's most powerful promoter, has already forecast potential big-money fights in Las Vegas or New York City.
