"The judges' scores would have greatly changed if the refs did their job properly. He didn't give Manny the respect and fair protection that is due to a people's champ."
Meanwhile, Pacquiao's iconic trainer Roach revealed that his fighter had shunned him after the fight in the locker room, perhaps fearing that he would be told to retire.
Roach also made the extraordinary admission that he "gave up" while working Pacquiao's corner during the fight, saying both cutman Miguel Diaz and Pacquiao confidante Buboy Fernandez had lost their heads.
"After watching the De La Hoya fight the night before and then this ..." Roach told Sports Illustrated. "I once kicked two guys out Johnny Tapia's corner. His wife helped me in the later rounds, in a short dress and high heels, going up and down the stairs. Here it was just so far off that ... I kind of gave up. That's unusual for me."
Roach, who said he would no longer sanction Pacquiao to face heavy-hitting younger fighters like Terence Crawford, said the 38 year-old "was definitely avoiding me" after the bout. He said Pacquiao was still keeping his distance.
"I really don't know if he's mad at me," Roach says. "But I can tell you this: I haven't been paid yet. So who knows?"
Roach said the Horn fight was the first time where he felt 'Pac Man' was simply not himself, indicating he thought the eight-division world champion was all but finished.
"It was almost over in the ninth. One more round like that and, man... He just couldn't do it. I would give him the benefit of the doubt and let him have one more. I would. Look, I wouldn't expect a new guy to come out there. I know what I have now."
Horn is still expected to take a rematch with Pacquiao. The Aussie reacted with relief to the news of his confirmed win.
"It's been good to clarify it because they have argued it. (Now) you can't dispute anything," he said. "It gives me evidence behind me that I can just use now. Instead of saying 'I think I won the fight', now a heap of other people - professionally - think I won the fight.
"It's definitely nice to have it finally put on paper. I thought I'd won the fight on the day and I think Pacquiao thought it as well. Now just to have it clear in front of us is good."
Horn took a shot at ESPN boxing personality Teddy Atlas, who has been accused of biased commentary that heavily impacted fans' perceptions of the fight.
"He kind of annoyed me a little bit after the fight. I'm on my highest moment and he's kind of dragged me down straight away," Horn said. "I'm not really a big fan anymore."
