And now, following a meeting with promoter Eddie Hearn and trainer Dominic Ingle, he claims he is ready to unleash the new-look Brook on his Argentine opponent, with a shot at the world title on the line.

"This fight is an important one for me and my team, I'm one step away from having a crack at being the world champion," Brook said.

"If Hector has gone off my last performance, well that wasn't me. Things have been addressed and I'm a different animal. I am in the best shape I have been in, and I have been fighting for 17 years.

"I'm eating well, drinking plenty and I have never been better. I am taking plenty of recovery time and I have had a brilliant 12-week training camp. I am pushing myself more than ever before.

"I want this more than ever and I have got the eye of the tiger. I have left no stone unturned and this Saturday you're going to see the best of Kell Brook - one that's good enough to take care of Hector Saldivia."

Brook showed his new shape to fans at a public workout in Sheffield last Friday, with the ripped physique apparent as he went through his paces with Ingle.

Unbeaten throughout his 28 fights so far, Brook has not got to where he is by being lazy but, according to his tactician, changes needed to be made and, so confident is Ingle that his man will prevail on Saturday, he has told him he may as well retire should he lose.

"We had two weeks after the Carson Jones fight where we sat down, myself, Kell, Eddie and two guys from Sheffield Hallam University - a nutritionist and a sport science guy - and looked at every aspect of Kell's performance and what went wrong," he said.

"Everything has been addressed. If Hector Saldivia has based his fight on the last one, he might as well have watched a different fighter. Every time you go into camp you say it's the best one you've had, but this has been.

"If he had have trained like this for Carson Jones, he would have won in four rounds. His attitude to training is different, every aspect from nutrition, training, hydration and sleep. If he doesn't win on Saturday he might as well hang his gloves up because he can do no more."

For the moneyman, Hearn, the changes have been welcome. He took Brook on 15 months ago with a clear aim of challenging for a world title but seeing him knocked around by Jones left him concerned.

He counts Brook not only as a fighter but as a friend and he believes he will be able to watch easier at ringside as a result of his man's new regime.

"I knew that Carson Jones would give us a hairy night if it went past six rounds and when he broke his nose, you not only think about your investment but your mate," said the promoter, who spent a large part of the day laughing off becoming the latest target of outspoken heavyweight Tyson Fury on Twitter.

"We've seen him embrace the new changes and the diet and he now realises the animal he can be. In a fight I don't think you've seen more than 60 per cent of what he can do yet."

Today was the first time Brook and Saldivia have come face-to-face, and as befits a fight that carries no previous baggage, their traditional square-up was a respectful one.

The 28-year-old, who has based himself at the Big Bear Gym in California for the past six months, spoke little, but did say: "Thank you (to Brook) for inviting me. I am in the best form of my life and I have been waiting for this moment for a long time."