The giveaway to his age is certainly not in how he plays tennis: His has a rangy, aggressive game with plenty of net skill—courtesy of doubles experience with elder brother Mischa.
It is not in his height—a generous 6ft 6ins—nor in the breadth of his shoulders.
It is certainly not in his accomplishment with languages: He is fluent in his native Russian and German, and near perfect in English too. Not only that: He is entirely at ease with every question thrown at him, confidently taking the microphone from its stand, making eye contact, answering with humour and intelligence.
Perhaps the only small clues to his tender years are the still-slender long limbs, and a youthful visage that belies that media-friendly maturity.
He also has enough confidence to talk of his achievements, while being smart enough to understand that he is only a year or two along the difficult road that leads to senior tour success.
Mischa helped me with my breakthrough. He’s been on the tour for so long and told me so many things about the players
Asked about his long-term dream, he paused: “I just want to win tennis matches right now. Obviously every kid’s dream is to win a Grand Slam. It’s obviously what I’m working for. But we all know it’s a long way to go.”
He freely acknowledged, too, that he still has to undergo more physical development before he can contemplate reaching his optimum condition.
“Yes, I’m still developing. A lot of ex players also told me that for tall players, it takes more time to develop than for someone who is shorter because everything is so much longer, so for us it takes longer to get to the highest level.
“From building up the body, building the muscles, everything is just a bit harder, but in the end it all pays off. You’ve got the advantage of being tall, you obviously can serve better, and if you make your body as strong as someone who is six foot, you can be a great tennis player.”
All that will take time, of course, but he has wasted no time in soaking up advice like a sponge from tried and tested sources. That began with his family: His father is a former player, his mother a coach, and his brother reached 45 in the rankings at the age of 21, though wrist injury sees him currently 100 places lower than his kid brother’s No70.
“We really support each other, especially Mischa helped me with my breakthrough. He’s been on the tour for so long and told me so many things about the players.
“I played three sports—soccer and field hockey. The club where I come from in Hamburg has one of the best hockey teams in Europe… But when I was 12 years old, I had to make a decision and there was not really any doubt that I would be a tennis player.”
Last week in Montpellier, Zverev reached the semis in the singles draw but also the finals in doubles with his brother, and that fraternal bond impacts on other parts of his life, too. Asked about his idol, the teenager used one word: “Roger”.
After a pause, he elaborated: “I mean Roger is my brother’s favourite player by far, so whatever your brother likes, you like. Also when I got to know [Federer] a bit on the tour, he’s even more my idol now—the way he acts and communicates with all the players.
“He’s been giving me tips on tournaments. He always takes me to practice…I don’t know why, to be honest! He’s been a big help, telling me how to act on court and what to do in the important moments.”
Certainly some of the Federer touch is more than evident in Zverev’s handling of media obligations, though he may want to nip in the bud the Federer tradition of taking press conferences in three different languages. The Swiss has lived to regret setting that early precedent.
But what better way to make the difficult transition from junior to senior ranks than with the guidance of those who have managed it so successfully?
“I think this generation, we’ve [made the transition] quite quickly. Even then, the first half of 2014, when I stopped playing juniors, I didn’t win much. I was playing qualies, playing Challengers, losing early in tournaments. Some people think it was easier than it actually was.”
Another mentor has come in the shape of Hamburg’s tournament director and former Wimbledon champion, Michael Stich.
“Yes, he has been helping me a lot. He was giving me a wild card since I was 16 into Hamburg, always talking to me, saying what he thinks I can improve, what he thinks I should do to beat certain players. It helped a lot with the confidence level on court.”
Stich, it seems, like Federer, has noted that the teenager not only has the physical wherewithal to be a fine tennis player but also a willingness to listen and learn about the sport on and off the court.
Next up for Zverev in Rotterdam is a first meeting with Gilles Simon, one of the toughest cookies to crack both physically and mentally. So the young German may find that Thursday is the end of this particular road, but with admirers like Federer and Stich in your corner—and now a good few tennis journalists, too—it is surely just a matter of time until he outstrips the ranking of that special older brother, too.