Amir Khan says his rematch with Lamont Peterson in Las Vegas in May will be "a make or break fight" for his career.
"Everyone knows I was treated unfairly, that's why this rematch has happened. All I want is a fair fight," Khan told BBC Sport.
"You're going to totally see a different Amir Khan this next fight."
Khan's grievances over the original bout concerned points deductions by referee Joseph Cooper for pushing and also the role of 'mystery man' Mustafa Ameen at the ringside.
The World Boxing Association (WBA) ordered a rematch, claiming there were "multiple irregularities" in the first encounter, giving Peterson 180 days to agree terms with Khan.
As the build-up to the re-match began, Olympic silver medallist Khan, 25, admitted for the first time he had struggled to make the weight for the first fight and made some mistakes.
"He's going to be different, he's going to be stronger, he's going to be more slick," said the Bolton fighter.
"I'm going to go into this fight and knock Lamont Peterson out this time.
"I want these titles to come back to Britain and I'm going to give it 100%."
Khan said he had begun his training two weeks earlier than usual, giving himself 12 weeks ahead of the clash on 19 May at the Mandalay Bay resort.
Peterson, who said his victory over Khan was the culmination of "18 years of work", has accused Khan of arrogance and added: "I'm willing to give my life up for these belts.
"That's the mentality you have to have as a fighter, as a champion.
"You don't just give those titles away. I've been in the gym training for 18 years and it wasn't easy."
Peterson continued to say he was "convinced" he won the first fight fairly in his hometown but insisted he was not angry with Khan.
"I understand that, a lot of times, when you lose, it's a hard pill to swallow," said the American.
"But now it's like, OK, you got the rematch, you get a chance to prove yourself, you get a chance to get your titles back."
He added: "It seems Team Khan still have problems with what happened in DC. I can only tell them that nothing shady happened, but I'm sure they won't take my word for it."