The author (On Being John McEnroe) and Observer correspondent speaks with mensvogue.com editor Ben Cosgrove about Roger Federer's mental toughness, his rivalry with Tiger Woods, and why Dubai—Federer's home when he's not on tour—might be a great place for pro athletes to live, but resembles nothing so much as a very large hotel lounge.

MEN'S VOGUE: Shortly after you filed your article on Roger Federer, he lost two matches in a row to Guillermo Cañas, a player ranked sixtieth in the world at the time. Had you spoken to Federer about his 41-match winning streak someday inevitably coming to an end?

TIM ADAMS: When I saw him, he was fresh off of winning the Australian Open without losing a set. He wasn't expecting to lose, though he did say that he goes into every match thinking that he might lose. But to lose twice, particularly to the same player in two major events, is probably a little bit troubling for him. He might be going into the clay court season a little less certain than he was before.

MEN'S VOGUE: Federer is only 25 years old. Do you think the losses might be the result of a young, very accomplished athlete meeting somebody who's not really of his caliber and simply not gearing up for the match?

ADAMS: I think so. Great tennis players have always struggled, particularly in the early rounds in tournaments when they've had a little layoff, and occasionally they come up against people whose game doesn't suit their own, and it sounds like Cañas might be one of those. One of the things that I talked to Federer about was how he tried to raise his game even when he was so dominant — how you go to these minor matches and keep your level up just in case you're having an off day and you come up against somebody who's on fire. He's interesting in that way, because he has these little strategies.