Amir Khan admits his career could be left in tatters if he fails to beat Lamont Peterson for a second time when the two fierce rivals lock horns again in May.
Khan surrendered his IBF and WBA light-welterweight titles last December after a shock defeat to Peterson in a controversial split decision in Washington.
Khan's team were incensed by the judges' decision to grant Peterson the win, and later complained to the IBF and WBA about the fight, in which the Bolton fighter was docked two points for pushing. Khan also questioned the presence of Mustafa Ameen at ringside.
The WBA ordered the rematch in light of "questionable decisions" of referee Joseph Cooper and an "apparent intrusion in the scoring process".
Khan has vowed to put any furore about the pair's original fight to bed by knocking out his 25-year-old opponent, but admitted that losing again could put a severe dent in a career that has been on a sharp rise since he won silver at the 2004 Olympics.
"This is a make a break fight for me because I have so much to lose now," Khan said.
"Now is the time to put things straight. I'm glad Lamont took this fight. I will be training like a challenger and I am going to prove to the world how good I am and prove that I am better."
The furore that followed last year's bout has led to strained relationships between the two camps and at one point it appeared the rematch would not happen.
Khan, who has had to delay plans for a meeting with Floyd Mayweather because of the Peterson defeat, maintains he was robbed but his opponent, unsurprisingly, denies that was the case.
"They know deep down inside who won," Peterson said.
"I am the champ. They know that there was no cheating going on."
Today's press conference to launch the rematch, which will take place on May 19 in Las Vegas, was a tense affair, with Peterson claiming Khan's camp had only kicked up a fuss about the original decision in order to mask what he thinks was a genuine defeat for the Lancastrian.
"They just used those tactics to get a rematch," Peterson added.
"Now that he has got the rematch, I think he should let it go and focus on May 19 before he loses an other fight.
"I think it will distract him, all this talk about the first fight.
"He still has it in his mind that he won that fight, he is focusing on that.
"He will think he doesn't have to change much to win again but he does."
Cooper had only dealt with a handful of world titles before officiating in last year's fight in Washington, and Khan felt both he and the judges were biased against him.
He is confident that the rematch, at the Mandalay Bay Hotel, will be fair.
"There will be a lot of changes. All I want is a neutral referee, neutral judges and a neutral venue.
"We were denied that the first time. I am sure that this time it will happen.
"We want a referee who is going to be true, who understands the sport well and who is neutral - he is not going to be from the same state as Lamont Peterson this time."
Khan hopes to avoid any doubt about the outcome this time around by knocking out his opponent.
"I am very determined to knock him out now. I will do a job on him," said Khan, who will train in the Philippines with Manny Pacquiao ahead of the fight.
Having grown up on the streets of Washington after being abandoned by his parents, Peterson does not fear his opponent's threats.
He said: "He doesn't scare me. He said he was going to knock me out before the last fight but it didn't happen and I don't think that's going to happen again. If anything I think that I could get the knockout."