In their own ways, Amir Khan and Lamont Peterson symbolise the value of ambition.

It is the trait that has drawn them together in Washington DC, the city of power and history, of American idealism. It is also one of the few experiences the two men share. When they take to the ring in the small hours of tomorrow morning and fight for Khan's two world titles, they will be distinguished by their backgrounds, their fame, their status, the courses of two lives that will only briefly intersect.

This is Peterson's city, where his childhood was spent living rough, scratching an existence on the periphery and almost succumbing to a life of drugs and crime. Boxing became a salvation, when he and his younger brother Anthony found a gym called Headbangers, and met their trainer and mentor, Barry Hunter.

For Khan, it is a place of privilege, where Hilary Clinton invites him to the White House and the ambassadors of Britain and Pakistan will attend his fight. Boxing was the sport that Khan's self-made and middle-class parents turned to in the hope that it would be a match for the endless energy and boisterousness of their child.

Peterson's family fell apart when his father, a crack addict, was jailed and his mother couldn't cope with their 11 children. Khan's life has always been stable and encouraging; a source of contentment that he still relies upon. Fighting is central to them both, though, because it came naturally, and offered a means to express their determination to succeed, to progress. Peterson was leaving something behind: poverty and hopelessness; Khan is chasing something: glory and stature.

The distinctions remain, since Peterson is approaching this title challenge in the understanding that, at 27 and as the underdog, it might prove to be the high point of his career. Khan is able to view the world as a place to be scaled, where the only limits are the chutzpah of his promoter, Oscar de la Hoya. Khan is increasingly being marketed as the sport's next illustrious figure, the coming champion of prestige and acclaim as much as boxing prowess.

In a country where capitalism and wealth are national creeds, where somebody like Peterson can be abandoned by society at the age of six and still find a way to redemption, Khan is being recreated. An heir is needed for Manny Pacquiao and Floyd Mayweather Jr, the two most esteemed boxers of their generation, and the 25-year-old from Bolton is in the prime position.

He even works with the fight game's most admired trainer, Freddie Roach, and has become a slick, increasingly well-schooled boxer. Khan is growing into his shrewdness, while the business machine around him works its calculating way. Every fight is framed by the opportunity it will create; he is a boxer forever advancing. He holds the World Boxing Association and International Boxing Federation light-welterweight titles and the last credible opponent after Peterson is Timothy Bradley, who has declined the offer of a unification contest, so instead Khan talks of moving up to welterweight, where Pacquiao and Mayweather reign.

Peterson cannot be dismissed glibly though, not least because he is fighting in his own city and the mix of pride and motivation can be potent. Roach believes this will be Khan's toughest contest, a recognition of the challenger's strength and relentless will, but also his own man's tendency to veer into showmanship. Khan is not an extrovert fighter, but he occasionally allows himself to fall back on the ropes and scrap with opponents. There are few flaws left for Roach to address, but he acknowledges that there is danger lurking in this contest and predicts that it will go the distance.

Khan will be quicker, more mobile, irrepressible, and he has shown in the past that he can take a heavy blow and recover. Peterson has, too, when he was knocked down by Victor Ortiz and recovered to earn a draw. He has also lost to Bradley, but is capable at this level. There is unlikely to be an upset, but only if Khan does not succumb to hubris.

"Amir is the future," says De la Hoya, but he cannot always live for the next assignment.

richard wilson