AMIR Khan has revealed his reluctance to insist on a rehydration clause for his May 7 fight with Saul Alvarez owing to his desire to make the biggest possible statement.

Bolton's former world champion will fight above welterweight for the first time in his career at a catchweight of 155lbs, officially middleweight, to challenge Alvarez for the Mexican's WBC title at Las Vegas' T-Mobile Arena.

Particularly given the significant difference in size between challenger and champion when they appeared together in London, it appeared a risky oversight that Khan did not demand a restriction on Alvarez's weight on fight night.

The Mexican's frame means there is little to stop him gaining a further 20lbs after weighing in to effectively compete at light-heavyweight and therefore leaving Khan, the underdog who turned professional as a lightweight, at an even greater disadvantage.

There is little question Khan's best chance comes in using his superior speed and mobility against his stronger opponent, so asked why he took such an unnecessary risk, he said: "I wanted to do everything naturally because when I beat him I wanted to beat him fair and square and I don't want people thinking 'He was too dehydrated, he was too small, he couldn't put weight on'.

"I want to beat the best Alvarez, fight the best Alvarez. The fights I've been watching he was really hydrated, and normal, where he was happy making the weight.

"Yeah (we considered a clause), I spoke to Virgil (Hunter, my trainer), and Virgil is the one who said to me 'Look, if you're happy with the fight, it's a good fight for us'.

"He's been watching videos (of Alvarez) as well. What I have to do is stick to the gameplan. I can't make any mistakes or be a guy who loses focus or makes mistakes because I can get hurt for that.

"I saw the videos, and they gave me so much confidence I thought 'This is the right fight for now'. I saw him being slow - being a big puncher, but for him to land he has to catch me."

Khan has made no secret of his frustration at repeatedly failing to secure what would be defining fights against Floyd Mayweather or Manny Pacquiao, but in the 25-year-old Alvarez - perhaps the sport's biggest attraction after those two names - he finally has the opportunity he has long sought.

His trainer Virgil Hunter - widely respected for his work in guiding the masterful Andre Ward - has a reputation as a disciplinarian so it surprised many that he agreed to a fight few believe Khan will win, but the 2004 Olympic silver medallist explained that Hunter needed persuading and also spoke of a belief his trainer could be his greatest asset come May.

"Yeah, he did (take persuading), but obviously he believes in me a lot," he told Press Association Sport. "When we sat down and spoke about it he said he thought it was a great idea to take this fight.

"Virgil Hunter's the one who's going to be the biggest help in this fight."

Alvarez is in the UK for the first time to promote his date with Khan. It says much about his profile in Mexico and the US that his first middleweight title defence is being used to open Vegas' new 20,000 capacity T-Mobile Arena, in which many expected Mayweather to be the first to feature.

"Amir Khan's a great fighter, a serious fighter, a serious threat," he said. "On May 7 this is going to be a great fight."