Sandra Zaniewska and the years before the breakthrough

On the first Saturday of May 2026, Marta Kostyuk won the WTA 1000 title in Madrid, the biggest of her career. In the box, applauding, was a Polish coach most casual viewers would not have been able to name. If you had joined the story that afternoon, it looked like a breakthrough. Somebody arrives, something clicks, a trophy gets lifted. That is how tennis is usually narrated, because a single week of finals is a shape a broadcast can hold and three years of Tuesday mornings is not.

Sandra Zaniewska had been coaching Kostyuk since July 2023. Nearly three years. Her own line about this, written on her newsletter The Unseen Court in May 2026, is the best sentence about coaching I have read this year.

It is a sentence about tennis, and it is also a sentence about record keeping, patience, and what a coach is paid to hold. It applies as neatly to a Wednesday evening lesson at a municipal court as it does to a centre court in Madrid.

The player who stopped at twenty five

Zaniewska was born in Katowice in January 1992 and was already a genuinely accomplished player. She reached world No. 25 as a junior in 2009 and was runner up in the girls’ doubles at the Australian Open that year alongside Aleksandra Krunić. As a professional she climbed to No. 142 in singles in August 2012, and to No. 203 in doubles that October.

Then her back gave out. Chronic disc problems narrowed what her body would agree to do, and she played her last professional match in June 2017. She was twenty five. That is a specific kind of ending. Not the retirement of somebody who has won everything and is tired, but the retirement of somebody who was still climbing and found the ladder taken away.

It matters to what came next. A coach who topped out at No. 142 cannot lean on her own trophies in the way a former champion can. She has no myth to trade on. Whatever authority she has in a player’s ear, she has to build week by week out of attention and accuracy. In practice that turns out to be a more transferable skill than a high ranking.

A record of slow climbs

Her coaching history reads like a sequence of long middles rather than quick fixes. She took on Petra Martić in 2018, when the Croatian was hovering around No. 90, and Martić rose to a career high of No. 15 and reached the quarter finals at Roland Garros in 2019. Then a spell with Alizé Cornet from December 2019. Then Kostyuk from July 2023: a first major quarter final at the Australian Open in 2024, the Madrid title in 2026, and back to back major semi finals at Roland Garros and Wimbledon that same summer. Zaniewska was nominated for WTA Coach of the Year in 2024, two years before the trophies people now associate with her.

Look at that list from the outside and you see four or five bright moments. Look at it from inside the work and you see something closer to eight years of ordinary days, most of them containing no result at all. The bright moments are real. They are also the thinnest slice of the thing.

This is the part of coaching that nobody films. A player comes off court flat for the fourth session running and you have to decide whether that is fatigue, a technical frustration she has not articulated yet, or something happening at home. You will not know for another month. In the meantime you keep showing up, keep noting what you saw, and keep resisting the urge to make a dramatic change so that you feel useful.

First the human, then the tennis

Zaniewska put her philosophy in five Polish words in an interview in February 2026: najpierw człowiek, potem tenis. First the human, then the tennis. It sounds like the kind of thing everybody says. She has been unusually willing to describe what it costs.

Speaking about coaching Kostyuk, a Ukrainian player competing through a war at home, she told Roland Garros: "I’m not living her life, she is. All I can do is give her a hug." There is no technique in that sentence and no plan. It is a coach naming the boundary of her own usefulness, which is a harder thing to say out loud than most coaching advice.

She has also been direct about the shortage of women in coaching boxes. Speaking to the BBC in June 2026, she argued that the communication and emotional intelligence a woman brings should be read as an asset rather than an exception. Both positions come from the same place. The relationship is the instrument. Everything technical is played on it.

Arriving on time to your own clients’ stories

Here is where the line stops being about tennis. Every coach reading this has a client whose breakthrough will one day look sudden to everybody except the two of you. A parent who says, out of nowhere, that something has clicked. The adult beginner who plays a whole set without apologising. Or the pupil who passes her grade exam and gets congratulated on being a natural.

You were there for the earlier chapters. The question is whether you can still read them. Because a coach who cannot recall what happened in March has, in a practical sense, also arrived late to the story. The chapters exist. They are not retrievable.

This is not a memory failing. It is arithmetic. A tour coach travels with one player and has a team around her. A solo coach might see twenty five people in a week, each with their own thread, their own last conversation, their own thing to come back to. Nobody holds that. What you hold instead is whatever you wrote down.

The coaches who do this well are rarely doing anything elaborate. Two lines after each session. What we worked on. What to come back to. Ten seconds reading it before the next one starts. Done for a year, that habit turns into something quietly powerful. It becomes a record of a person’s development that neither of you could have reconstructed from memory, and it makes the eventual breakthrough legible as the long thing it was.

What the record gives back

There is a moment, usually in a conversation with a parent or a client who is thinking about stopping, when the record earns its keep. You are asked whether progress is being made at all. Without notes you say yes and hope you sound convincing. With notes you can be specific: this is what she could not do in February, this is what she did on Tuesday, this is the thing we are still working on. The doubt tends not to survive the specifics.

It also protects the coach. Development is not linear, and a flat month feels like failure when you are inside it. A record is the only honest way to tell the difference between a plateau and a genuine problem. Zaniewska’s Martić climb from No. 90 to No. 15 did not happen in a straight line either. Nobody’s does. The line looks smooth only once it is drawn from far enough away.

And it changes how the good weeks land. When something finally clicks and the client says it came out of nowhere, you get to tell them the truth. It did not come out of nowhere. It came out of nineteen sessions, three of which were miserable, and here they are.

Where to read her

Zaniewska writes about this side of the work more openly than most people at her level. Her newsletter The Unseen Court is exactly what the title suggests, the part of performance that never makes the highlights, and her podcast More Than Points covers similar ground for coaches, parents and players. She is also building a coach and parent education programme called Raising Champions, which currently has a waitlist open, alongside her own writing on developing players.

We have no arrangement with her and nothing to gain from saying so. We link to her because she is describing, from the top of the professional game, the same thing we built a product around. The work worth doing is mostly invisible and mostly slow, and it only makes sense if somebody is keeping the record.

Most coaches will never stand in a box in Madrid. Every coach can decide to be early to the story rather than late to it. That decision is made in the four minutes after a session ends, when you are tired and the next client is already waiting, and you write the two lines anyway.