Teddy Atlas lashes out at 'immature' Jeff Horn

American commentator Teddy Atlas is refusing to apologise for his comments about Jeff Horn and has stepped up his attack on the Aussie boxer.

Atlas caused a massive stir after Horn's incredible win over Manny Pacquiao last month when he told Horn to his face that he didn't deserve to win.

He later ranted about how corrupt the boxing world was and how the Horn-Pacquiao decision 'stunk', sparking a raft of criticism in the States from a number of high-profile figures.

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And even though the WBO later reviewed the scoring of the fight and still awarded the victory to Horn, Atlas is refusing to back down.

"End of the day I thought there was one winner and I gave it to Pacquiao," Atlas said in an interview with News Corp.

"Horn was missing a lot and you don’t get points for missing. You don’t win fights for trying hard. You win for being efficient and effective."

Atlas also said the WBO review means nothing because it was the same organisation that scored the fight initially.

"Same organisation. Do you really think they are going to embarrass themselves and say “we got it wrong?” What do you think they are going to do?" he said.

"Go and get a separate group of people from a different organisation. A group that is non biased and had nothing to do with the first fight."

Horn said he'd lost a lot of respect for Atlas after his controversial comments, but the American reckons the Aussie needs to grow up.

"I laugh at Horn. God bless him. It’s good for his country and good for boxing. I’m happy for that. But for Jeff to say “oh I lost respect for Teddy” … well grow up.

"You’re a world champion now. Say something little bit more mature than that. Are you kidding me?

"I expect something better to come out of the mouth of someone who showed that much grit and that much heart. I’d like to see him respect honesty."

Meanwhile, Horn is ramping up his preparations for a likely rematch with Pacquiao and reckons he can go one better this time around.

“Manny will probably be better prepared for me in this fight. He knows what to expect now but I will fight differently to our first bout and bring some more surprises," Horn told Fairfax.

“I’m really happy to fight the rematch because I copped so much flak over the points decision.

“But I’ll beat Manny even more convincingly this time. I don’t want to say I’m looking for the knockout but a KO certainly puts all arguments away.

Horn's trainer Glenn Rushton says Pacquiao has told his promoter Bob Arum that he wants the rematch and is not looking to retire.

“I want Jeff to be the only man in history to have beaten Pacquiao twice," Rushton told Fairfax.

“Manny’s pride is at stake. He has always done well in rematches and he needs money to fund his lifestyle and his huge charity projects so he will be confident of revenge."