Amir Khan curbs his enthusiasm for his battle with Barrera

Khan insisted he has heeded the warning sounded by American trainer Freddie Roach, that defeat against a three-weight world champion caused by his natural impetuosity will leave him with nowhere to go.

The 22-year-old former Olympic silver medallist has established a reputation for speed, throwing his fists in a blur of leather. In the past, that ability has fuelled a desire to dispatch his opponents in the quickest way possible with little regard for measured defence.

Last September that risky style cost Khan his only defeat in 20 professional bouts, when he left himself open to Columbian Breidis Prescott and was battered to a halt in just 54 seconds.

He knows he cannot afford the same mistake against 35-year-old Barrera as both men fight for the right to challenge WBO world lightweight title holder Juan Manuel Marquez.

Khan said: "I'm going in against someone who is a legend and he's not going to go down easy. Barrera can fight, he can box and he's a great counter-puncher who can still use a pressure-fighting approach.

"It's going to be tough. My career is on the line so Freddie's got me using a lot more technique, rather than heart, and throwing a big volumes of shots. Freddie's told me I have got to be smart, too. It's going to be about knowing when to throw and when to be patient and it's going to bring out the best in me."

Nothing less than Khan's best will do. He was just a two-year-old toddler when Barrera stepped through the ropes for the first of his 72 professional fights.

Two decades on, Barrera remains driven to become the greatest of Mexico's boxing champions. Already winner of world titles at super-bantamweight, featherweight and super-featherweight, he has now stepped up to enter Khan's lightweight division with the aim of dominating it.

"That's what got me into this fight," he said. "I know I can retire and be a legend right now. But I am only 35, I still have a lot to give to boxing. Retirement will come one day. After two or three more fights. But not yet. If I beat this kid, it will give me a shot at the lightweight title. That is what is driving me, the chance to be the first Mexican to be a world champion in four divisions. I want to write my name in history."

The intriguing question that is expected to draw a full house of 19,000 to the MEN Arena is whether Barrera, who effectively ended Naseem Hamed's career nearly eight years ago, can back up that confidence with boxing competence that has not be wearied by age. Three fights ago he lost for the second time to Manny Pacquiao, Roach's principle charge who will go in against Ricky Hatton in May, and Frank Warren believes now is the time for Khan to make his mark in the world.

Warren, Khan's promoter, acknowledged there is a big element of risk in pitching his man against a fighter of Barrera's experience. But he said: "There are fights that you should grab when you get the opportunity. And there are fighters you should grab when you get the opportunity. I believe this is one of those moments."

Warren also has high hopes for London's Nicky Cook, who on the same card faces a testing first defence of his WBO world super-featherweight title against unbeaten Puerto Rican Roman Martinez. He said: "Nicky wants to unify the titles and that's what we are looking to do later in the year."