“But the kids are healthy, they are happy, and Mirka doesn’t want to be away from me, and I don’t want to be away from her,” he added, “and like this we make it all work that we are actually together all year long, and maybe miss the girls and Mirka maybe one or two weeks during the year, which is just incredible that she’s willing to make all of that effort. I’m happy that it’s this way, because anything else would make it more difficult to compete and to play at the highest levels. It would basically be impossible.”

Federer is hardly the first tennis star to travel with family in tow. Andre Agassi, Lleyton Hewitt and Ivan Ljubicic all juggled fatherhood and the nomadic life on tour. Kim Clijsters has won three Grand Slam singles titles as a mother. But at the moment, the only other father among the top 20 is Gilles Simon, No.12 this week. What separates Federer from the crowd is that he already has secured his fortune and legacy — a record 16 Grand Slam singles titles — yet has shown no hint of losing his appetite for the game or the road, which is certainly more palatable with a private plane and other highest-end comforts.

But there is still a toll, and it is seldom the megastar who pays the highest price. “How important is the support from your wife? Hard to say, but to win Grand Slams, nothing can be more important than you winning,” said Mats Wilander, the former world No.1. “I think Roger will win again, whether he has the support or not from his wife and family, but yes, if your family travels with you, it’s harder on them than you. As a player, you’re as selfish as anything and as a supporting cast you have to be the opposite.”

The difference here perhaps is that Federer is an involved enough parent to tolerate middle-of-the-night wake-up calls from the twins during tournaments. The bigger difference perhaps is that Mirka was once a player herself.

“I think it’s a great help that she actually played,” Federer said. “I never started dating a tennis player because of that, actually, sort of 10 years ahead. But in my situation, I think it really does help, because she knows in some ways what it takes, and she did it on a level that was still very good but not at my level. And she already put in a massive amount of hours herself. So when I tell her, ‘Look, I need to go to practice,’ she’s the first to say, ‘I know, I know you need it, and you need only maybe 20 percent of what I needed.”’