Usually, however, it is only Serena and Venus we are talking about. And they are on opposite sides of the net.
This year's ladies singles final provided a variation on a theme. After clinching her fifth singles title in South West London with a 6-1, 5-7, 6-2 victory over the defiant Pole Agnieszka Radwanska, a clearly emotional Serena Williams climbed to the Royal Box to embrace her father Richard, mother Oracene Price, hitting partner and fiancee Sasha Bajin, and surviving sisters Lyndrea, Isha and Venus. She then singled out Isha, physical trainer Esther Lee, personal assistant Val Vogt and agent Jill Smoller for helping her get from a hospital bed to where she is now. As Wimbledon acceptance speeches go, it was a full-on Halle Berry.
As she drew level with her big sister by lifting the Rosewater Vase for the fifth time – "I've always wanted everything that Venus has had," she joked –Serena was more than entitled to indulge her emotions yesterday.
A combination of ailments, the worst amongst them a serious foot injury and pulmonary embolism, have dogged her over the last 18 months, and contributed to her absence from the winner's rostrum in the last seven Grand Slams.
Even when she was in the relatively safety of the interview room, she had difficulty keeping it all together.
"There was a moment I was on the couch and I didn't leave it for two days," Serena said. "I was praying, saying I can't take any more, I've endured enough. I was just so tired at that point. I had a tube in my stomach and it was draining constantly.
"Right before that I had the blood clot. I had lung problems. You know, then I had two foot surgeries. Coming here and winning today is amazing because, you know, literally last year I was ranked almost 200. It's been an unbelievable journey for me.
"Esther, Val and Isha in particular, and Jill, from the day I got to the hospital until the day I left, they never left the room," she added. "They slept there, all three of them. And they didn't have to do that. My sister Isha owed me that, but Esther and Val definitely didn't. That meant a lot to me. I remember Esther came up to me and she was like 'God is really going to help you through this'. I think she saw that I was really, really, really down. So that really helped me. Or else I would still be there."
Serena may have received special care in her hour of need, but only briefly did she show any mercy to her Polish opponent yesterday. Radwanska became the first male or female Polish Grand Slam finalist in the open era yesterday – her countrywoman Jadwiga Jedrzejowska made it to three major finals during the 1930s – but, watched by comedians Michael McIntyre and Miranda Hart, most of this first set was no laughing matter for her. She had been struggling pre-match with a sniffle, and the cool, windy conditions couldn't have helped. At first she did well just to get a game on the board, and could well have been bundled out of the contest in double-quick time were it not for a rain delay.
Williams also led the second set 4-2, but the 2005 girls' champion here hung in and for a while it seemed her clever tactics and fleetness of foot might pay real dividends. She broke back for 4-4 and took the first of three set points to take this into a decider.
But that brutal Williams' serve, the shot par excellence of the entire women's tournament, told in the end. One game in the final set was over in just 49 seconds, courtesy of three Williams aces, and after she wrapped up matters 6-2, by the end her tally stood at 101, a record for the women's game. "That's my latest and greatest thing to do, is hitting four aces in a game," Serena said. "My serve really helped me throughout this tournament. I can't describe why it was so good. It's not like I practice it that much."
While her opponent was just happy to be there – "These are the best two weeks of my life," she said – Williams became the first woman aged 30 or over to win a Grand Slam singles title since Martina Navratilova in 1990. But this was a beginning rather than an end for Serena, who was due back on Centre Court with Venus for the ladies' doubles final against Andrea Hlavakova and Lucie Hradecka. Ominously, she has never felt better.