Belgium has Kim Clijsters and Justine Henin, Serbia has Ana Ivanovic and Jelena Jankovic, China has Li Na and Zheng Jie. Like women going off to powder their noses on a night out, female tennis players often seem to be in pairs. Might two Britons be about to follow that trend?
Without wanting to hang too many expectations on the young shoulders of Laura Robson and Heather Watson, the potential of Britain's two junior Grand Slam champions was evident last week in the improbable setting of the Aegon Pro-Series tournament at the Tarka Tennis Centre in Barnstaple, Devon.
Watson, the 17-year-old from Guernsey who last month became the first British girl to win the US Open junior title, beat Mel South, the British No 4, while 15-year-old Robson, last year's junior Wimbledon champion, stretched Naomi Cavaday, the British No 5, before losing a tightly contested match. Poor South was on the receiving end again in the doubles, losing to Watson and Robson despite teaming up with Sarah Borwell, the world No 77.
After her triumph at Flushing Meadows, Watson has been enjoying most of the recent media attention, though the Robson camp are not complaining. "I think it's a blessing," Martijn Bok, Robson's Dutch coach, said. "It provides a bit of extra motivation for Laura. That's why some countries get a group of great players. They all push each other to the next level. I really hope Heather keeps doing well so they can push each other along."
It helps that the girls and their families get along so well. "Kathy [Robson's mother] is lovely," Michelle Watson, Heather's mother, said. "She invites us for tea. She makes lovely tiramisu."
The girls' closeness was clear in Barnstaple. "I was so pleased Heather won the US Open," Robson said. "We're really good friends." Did she see Watson as a big rival? "No way. She's too nice."
Watson has been at the Nick Bollettieri academy in Florida since she was 12. Robson, too, is looking to further her tennis education away from the Lawn Tennis Association's centre at Roehampton. She has spent some time at the Mouratoglou academy in Paris, the base for a host of rising young talent headed by Anastasia Pavlyuchenkova, Grigor Dimitrov and Michelle Larcher de Brito.
"I think we'll practise there more often, though we'll still come back to the LTA every now and then," Bok said. "Laura can just do her own thing there and she doesn't get distracted so much. It's important that she likes it. We wouldn't push her there if she didn't like it. I always say to people: she's Laura there, not Laura Robson. Just Laura. We practise on the back court, nobody's watching, we do our business.
"They have all the facilities – not maybe as new and flashy as at the LTA, but they have everything there. They have physical trainers, physios, nutritionists. Everything is there, but she can just be Laura. She's just one of a group of world-class juniors. I think that's a good thing."
Having become the first home player since 1984 to win junior Wimbledon last year, 2009 has been an up-and-down season. After reaching the Australian Open junior final, an injury scare kept Robson out of competition for three months, although it proved to be nothing more than growing pains. She returned on clay, her least favourite surface, and had a moderate grass-court season that was highlighted by taking Daniela Hantuchova to three sets at Wimbledon.
At the US Open, Robson then reached the junior semi-finals before losing to Russia's Yana Buchina, despite winning the first set 6-1. In the final round of senior qualifying she was 4-0 up in the third set against Eva Hrdinova, only to lose 7-6. Afterwards Robson admitted to having trouble breathing as she tried to fend off a panic attack.
Looking back on the experience, Robson agreed that "something wasn't quite right". What exactly? "I wish I knew," she said. "But that was in the past. I'm over it."
Bok explained: "She lost a bit of focus when the other girl took an injury time-out. She started thinking a bit too much and that's something she needs to learn from. It was an ugly experience, but in one way it was a good one. She learned from it and she'll try to make sure that it doesn't happen again.
"I've told Laura that she's lucky to be able to experience these sorts of things at this age in fairly low-key surroundings, even though it was at the US Open. Look at girls like [Dinara] Safina and [Ana] Ivanovic. They're dealing with the pressure now. Safina can't handle being world No 1. Ivanovic couldn't handle it. I think they maybe never had this kind of pressure when they were juniors."
Bok said Robson was a good learner. "Most of the time the good touch players can be a little bit lazy, but Laura has improved a lot in that area and is really working hard in practice. She hasn't won many matches this year, but I'm very happy with her progress. I see her in practice and I see what she can do.
"If Laura looks back, she will actually think this was a very important year. She has learned how to deal with a lot of different things. When I work with Laura I don't look at her now or even next year. I look at her in three, four or even five years."
It is easy to forget that Robson is still only 15. She is a wonderful ball-striker, with big ground strokes and a potent serve – the perfect game to take into the adult arena. If her movement has been a weakness, recent hard work in that area is clearly paying off.
The immediate challenge is to find enough matches in which she is stretched. She is likely to play four more senior events this year, but rules designed to avoid teenage "burn-out" restrict the tournaments she can play.
Robson is unlikely to play many junior events outside the Grand Slam tournaments next year. "If you play a junior tournament which isn't a Grand Slam you might get a good match in the semi-final or the final, but that's not enough," Bok said. "Laura needs more matches, just to get the experience of playing different matches, against different opponents and using different tactics."
While Andy Murray is away, his rivals are making hay, writes Paul Newman in Shanghai. The 22-year-old Scot, who is nursing an injury to his left wrist, pulled out of both last week's Japan Open and this week's Shanghai Masters, as a result of which he will lose his world No 3 ranking in eight days' time.
Except for Roger Federer, who withdrew citing exhaustion, all the other leading players will be here for the season's penultimate Masters Series event which starts today, although Novak Djokovic will be a late arrival following his run at the China Open in Beijing.
The world No 4's semi-final victory yesterday over Robin Soderling guarantees that the Serb will swap places with Murray when the list is updated next week, irrespective of what progress he makes here.
US Open champion Juan Martin del Potro, the world No 5, can also make significant inroads into the lead Murray has over him. Murray is due to return in three weeks' time in Valencia, after which he will play in the final Masters event in Paris followed by the Barclays ATP World Tour Finals, the end-of-season showpiece at the O2 Arena beginning on 22 November.
The top seed here is Rafael Nadal, although it remains to be seen how close he will be to recapturing his best form.
The Spaniard returned to action in Beijing last week following the abdominal injury that hampered his US Open campaign and he looked badly out of sorts yesterday in losing 6-1 6-3 to Marin Cilic, Murray's conqueror in New York. Cilic meets Djokovic in today's final.
The world No 2, who has not reached a final for five months, lost the first five games in just 15 minutes. Nadal said: "Cilic is good, is young and has a very good serve but if you are losing 6-1 6-3 there are a lot of things you are doing wrong. Mentally I probably wasn't there."