When Roger Federer, the current world number one tennis player, is asked for his thoughts on cinema, he admits to a sneaking admiration for the similarly top-ranked spy, James Bond. In light of this, it is less surprising that for each game during his fourth successive Wimbledon championship last month, Federer wore on court an off-white cotton twill jacket to suit any past 007 with a personal crest on the breast pocket.

This coming Monday at New York's Flushing Meadows, Federer begins the defence of his US Open title. Free from the whites-only dress restrictions of the All-England Tennis Club, Nike's Jason Phillips, who designed the Wimbledon jacket now in the on-site tennis museum there, has devised a contrast for the next fortnight. For Federer, this time expect more Big Apple street-wear than strawberries and cream bespoke, according to Riccardo Colombini, Nike's Global director of tennis.

Federer's agent, Tony Godsick of IMG, says the Wimbledon jacket worked because the cut - based on one of Federer's own classic Prada jackets, without Nike's "swoosh" logo - was respectful to the game's spiritual home. Whether the new one will have the same talking point effect remains to be seen, but it may herald a further foray into fashion for the champ or perhaps, even, an extended clothes range.

In other words, if the new jacket gets as much attention as the old, tennis's current all-star could find himself battling for sales with other sportsmen such as former Test cricketer Darren Gough, poised next year to develop his own fitness gear after success in the celebrity reality television show, Strictly Come Dancing.

The power of sport to shape trends from George Best boutiques and Michael Jordan trainers through to David Beckham today should never be underestimated. Most recently, Zinedine Zidane created a stampede for the military style jacket he wore draped over his shoulders during his television apology for getting himself sent off in the World Cup final.

Yet the competitive nature of the leisure gear market - too tough for the denim underwear range developed by the current Barcelona football coach, Frank Rijkaard, after he retired from playing - means that Federer and Gough could share the experience of Wayne Rooney. In 2004, the footballer reportedly had to put on ice his plans for his own range.

According to Clifford Bloxham, a vice president at the global sports marketing group Octagon, which represents Gough - and Darcey Bussell, who endorsed a Marks and Spencer sports wear range in 2002 on the back of her standing in ballet - Rooney-wear stalled ahead of the player turning 19 because the initiative was premature. Unlike, for example, Federer's rival, Rafael Nadal, who may be the same age but already has his own clearly defined "blood and guts" persona, Bloxham believes Rooney's personality had yet to evolve sufficiently to carry a clothes range.

Federer, 25, with a classic image, wouldn't have such a problem, says Bloxham. The ponytail of his past, very much at odds with the sophisticated look he sported at Wimbledon, has gone. "These days, Federer is seen simply as class," Bloxham argues. Riccardo Colombini adds: "Roger might not even have been interested in a Wimbledon jacket two years ago."

As Federer makes his way in fashion, he has the comfort that, of all sports, tennis is unsurpassed as a basis for launching leisure wear. The game is unique in having sustained three named brands: Lacoste, Fred Perry and Sergio Tacchini. "The court is the perfect showcase," Bloxham says. "You are in vision for hours along, largely, with just one other person. Only golf can compete and then you are out of shot for minutes at a time, even Tiger Woods."

Further proof of tennis's strength is its ability to sustain a men's perfume range. Estée Lauder collaborated with Andre Agassi in 2003 to produce Aramis Life. This was highly successful, according to Roja Dove, a professeur des Parfums,because the brand sought only an association with Agassi. "Men could buy into the lifestyle of one of the world's best tennis players," he says.

Associations such as the one between Brut and the alpha male of his day, Henry Cooper, rather than own brands, work best with perfumes, according to Dove. Named brands, such as the scent David Beckham launched last year, can infer excessive intimacy. "Men were being invited to 'splash on a bit of David'," Dove points out. "In the same way, I'd doubt that an 'Eau d'Agassi' would have been popular."

The essence of Federer was subtly stitched into his Wimbledon jacket. "It was very personal," maintains Colombini. The breast pocket crest featured three rackets, one for each of Federer's titles prior to 2006, a Swiss national cross honouring his nationality, Leo shaped detail acknowledging his star sign, and tufts of grass highlighting his favourite playing surface.

If Federer was to go one step further, as his agent suggests, with his own leisure range, his sporting credibility will help greatly. The Hollywood actress, Scarlett Johansson, was last month signed by Reebok to front a planned "Scarlett Hearts" clothing and footwear range but "Johansson has no sporting credentials," warns Clifford Bloxham. "Association with artists like her works - but only if the range is pure fashion." Clifford adds that collaborations between, for example, Stella McCartney and Adidas, are different, again, as they are based purely on design. "[Stella] was never saying, 'wear these clothes, I wear them'," he observes.

Of course, luck plays a part in sportsmen successfully crossing over into fashion. New York Nicks legend Walt Frazier was in the habit of wearing Fedora style hats. These earned him the nickname Clyde largely because Warren Beatty had sported similar headgear as Clyde Barrow in the 1967 film Bonnie and Clyde.

But the most important factor of all when it comes to own-brand leisure wear is that the athlete involved is successful. The golfer Ian Poulter would struggle to shift a range of the more outlandish trousers he has worn in major tournaments like the British Open until he has actually triumphed in one of them.

Approaching the peak of his powers, however, Federer is already revered. When Wimbledon's museum dry-cleaned his jacket, the sleeves' creases were left unpressed for posterity. Thus, the US Open is merely the next stage in his attempt to conquer not just tennis but fashion.