Boxing: It's make or break time for the new model Khan

Tangled web: Amir Khan has been defeated twice in the past year, lost his world title and faced a tabloid exposé (Getty Images)

Amir Khan turns 26 today but he must wait a week before acknowledging wishes for many happy returns. For when he wakes up next Sunday morning he will know if the party's on... or over.

His 12-round fight with the unbeaten Californian Carlos Molina in Los Angeles will either mark a new beginning or the untimely end of an eight-year professional career that has seen him become an emblematic, racially harmonising figure in British sport. Like Khan himself, that image has taken a bit of a bashing these past 12 months, with two defeats, the loss of his unified world light-welterweight titles and the sort of tabloid exposé which might have qualified him for membership of the Hacked Off campaign.

Shortly after announcing his engagement to the beautiful American Muslim heiress Faryal Makhdoom, Khan was featured on the front page of a Sunday red-top allegedly "romping" in Marbella with a couple of girl holidaymakers, one of whom was quoted as warning his 21-year-old fiancée: "Don't marry him, he's a cheat." There followed descriptions of "frolicking" with pals in a hot tub. Khan insists it was all harmless holiday fun with a few mates, and that no sexual activity was involved.

Nonetheless it was hardly the sort of publicity his new commercial agents, Saatchi and Saatchi, wanted to project as they picked up the pieces after his ring setbacks, a situation exacerbated when Khan subsequently alienated the US media by mistakenly seeming to suggest that one of the reasons why he decided to leave the revered trainer Freddie Roach after his last stoppage defeat – against Danny Garcia in the summer – was because Roach's work had become affected by incipient Parkinson's disease. Khan promptly apologised for the comment.

He admits that 2012 has been a difficult and embarrassing year and that mistakes have been made. But he claims his popularity remains undiminished. "The public know who Amir Khan is and what he is about," he says. "In the past 12 months my Twitter following has gone up by about 700,000.

"I am beautifully focused, and if anything it has made me work harder and be even more determined to get back to the top. I've changed a lot of things in my life and it's just about moving forward now." To that end he has transported Team Khan from Roach's Wild Card gym to the one in San Francisco where his new trainer, Virgil Hunter – his fourth in as many years – has been working on acknowledged defensive frailties.

We are promised a new and improved model. "You'll see a changed Amir Khan," Bolton's Olympic silver medallist tells us. "I won't be making the same mistakes again. I don't need to get into wars. I know I can give opponents boxing lessons and I'll stick to that."

Hunter's approach to Khan is more headmasterly than that of the fatherly Roach. "I think he needs to be that way," says Khan, "because he knows how I was before, doing things how I wanted them done and not listening. Now I'm listening more, which has gone back to how it was when I was 17 and still learning."

"Keep him away from punchers," was the parting shot from Roach, and in selecting fellow Golden Boy Molina, also 26, for Khan's 30th bout his camp appear to have done exactly that. Molina has not lost in 18 fights but the majority of his opponents are relatively unknown and he has stopped only seven of them.

On paper it should be a reasonably comfortable comeback for Khan. In the ring it may be different if, as some fear, extracurricular activities – including huge amounts of charity work – plus the recent series of taxing contests have taken a worrying toll on his career.

Have we seen the best of Khan or, as the man himself insists, is that still to come? No one is more aware that his career will go belly- up should he take another beating.

There can be no questioning his bravery, but can you teach a bold dog new tricks?

Khan v Molina is live on Sky Sports 1 HD and on mobile and tablet devices via Sky Go next Sunday from 2am