Heather Watson looks a little careworn. She sounds it, too. Sinking back on a sofa in a subterranean green room at the Royal Albert Hall, her drowsy speech betrays every rigour of the 111/2-month season she has just endured.
The smile and the signature effervescence are mysteriously absent. Perhaps it is the London chill that distresses a girl more used to the honey glow of Florida sunshine, or perhaps it is the sense of a homecoming that makes her pine for a more settled existence, but within a minute her thoughts have turned to loneliness.
"Lots of times I feel quite lonely," she says. "I just want to go home and see everybody, because I hardly get to see my friends and family during the season. It's really tough, always living out of a suitcase or in a hotel.
"Playing your match, then going straight back to your hotel room - you're on your own a lot."
She stares across the room, pensively. Ostensibly she has so much to toast from 2012, not least her maiden WTA title in Osaka and her memorable tear to the third round at Wimbledon, but it is plain she finds the itinerant circuit that she inhabits a trial. Part of the problem, perversely, is her personality: her natural gregariousness stands out more starkly among the legions of ice maidens in the upper echelons of the women's game.
"I don't really fit in," she accepts. "I couldn't be mean and not talk to people if I tried."
Does this sharpen the feeling of solitude? "Definitely. But I suppose I understand why some of the girls have to be that way. They believe that it allows them to focus. In their minds, they're not playing a friend, they're playing an opponent. That's the job. It's difficult, though."
Watson keeps a limited circle of friends on tour, drawing comfort mainly from the company of fellow British starlet Laura Robson and her doubles partner, New Zealand's Marina Erakovic. Already she is steeling herself for a resumption of her globe-girdling treadmill, beginning in 10 days' time in Auckland, en route to her second Australian Open. It is a time of year which, based upon her experience 12 months ago, she does not exactly savour.
Last Christmas Day, she sprained her ankle playing football and did not advance beyond the first round of a single tournament for three months.
She looked hollow and forlorn when her debut in the Melbourne main draw ended in a 6-1, 6-0 filleting by Victoria Azarenka, and she does not shrink from describing the tailspin of bleak self-questioning that ensued.
"I went on a four-match losing streak, which had never happened to me before. I just got really depressed, and unhappy, and every morning I thought: 'Oh, I just don't want to play. I don't want to get out of my bed.' I went through a really bad period. Eventually I managed to get myself out of it, with a decent week in Miami. But it was one of the lowest points I've ever had playing tennis." Watson admits she was unrecognisable from the exuberant Guernsey girl to whom we have grown accustomed.
"There was a big change in my demeanour. I was losing and I just thought to myself, 'What's the point?' I got super-negative. It was a big struggle, awful in fact. This is what I love to do every day, what I want to do. So when you hate it, it just doesn't seem right."
The 20 year-old knew she had to recapture her customary irrepressible self.
Changes were essential, and none were more wrenching than her decision to drop her Papua New Guinean mother, Michelle, from her support team.
Mother and daughter had been inseparable from the moment in 2006 when Michelle - leaving husband Ian, once managing director of Guernsey Electricity, back home in the UK - decided to support Heather throughout her time at Nick Bollettieri's academy near Tampa.
The on-tour dynamic was ultimately unworkable. "It was essentially us just arguing all the time," Watson explains. "That didn't help my mental state. By myself, I'm able to focus much better. Say if you're travelling with somebody, you're dependent - I wouldn't even need to think about which gate I had to be at for a flight, because she would already be there. Left to your own devices, you're conscious of everything, and that's why I found it easier to be professional."
She is all too aware, she argues, of the precedents in tennis for volatile mother-daughter relationships. When Martina Hingis famously threw a tantrum in losing the 1999 French Open final to Steffi Graf, she had to be dragged back on court by mother Melanie for the trophy presentation. According to Watson, "sometimes it's better for my mum just to be a mum, rather than trying to coach and getting too closely involved". Over this, her breakthrough year, she has assigned each of her parents clearly defined roles.
While her mother remains the emotional sounding board, her father is the strategist and diary manager, plotting Heather's attempt next year to break into the world's top 10. "Before it was all about top 100, top 50," says Watson, ranked 49th. "Now it goes by 10s. My dad is always very realistic with me. He asks: 'Hev, do you think tennis is for you? Or should you go back to school?' He is very honest, and that has been so important in my career."
Watson exudes a confidence about the impending campaign, which she attributes almost solely to her triumph in Osaka, where she became the first British woman since Sara Gomer in 1988 to clasp a WTA title. It mattered not at all that she did not beat a top-50 player to do so, but simply that she had purged her simmering frustration.
"I was starving for that. I really, really wanted it. Ever since it has motivated me hugely."
There is still something missing on Watson's 2013 shopping list. Casting a crafty eye over London's department store windows, she has spotted a pair of Christian Louboutins that she hopes fervently to unwrap for Christmas.
"I've liked them for ever. It's the pointy-toe grey suede pump - that's what I want." Does this mean, dare one suggest, that she is turning high maintenance?
"No, no. The other day, I went to H&M and I bought three tops, all for a quid each. I still search for the bargains."
She breaks, at last, into that luminous smile.