Marta Kostyuk is through to her first WTA 1000 quarterfinal on clay at the Madrid Open, yet another breakthrough achieved in partnership with Sandra Zaniewska.
Zaniewska, the 33-year-old Polish professional player turned coach, has enjoyed a fruitful partnership with the Ukrainian rising star since they joined forces almost two years ago.
In that time, Kostyuk reached her first major quarterfinal at Australian Open 2024, ended that season at world No.18 – her first year-end top-20 finish – and in 2025 has already reached the quarterfinals at two WTA 1000 events.
Zaniewska has proved an impactful coach since her playing career ended and is one of the few female coaches working at the elite professional level.
Having previously guided veterans Petra Martic and Alize Cornet, she revealed she was enjoying the prospect of working with 22-year-old Kostyuk, a player at a very different stage of her tennis journey.
"For me it's the feeling that I can make an impact on someone, and really make them better,” Zaniewska said on this week’s episode of The Sit-Down podcast, when asked what she most loves about coaching.
PODCAST: Sandra Zaniewska on The Sit-Down
“As a player is one thing, but also as a person, right? Because you spend so much time with that person, and I feel like my first two players were older than me, but Marta now is 10 years younger. She's still at the stage of just growing, of evolving, of becoming the version of herself that she really wants to be, for the other part of her life, for the maybe more 'grown-up' I would say part of her life later on.
“For me witnessing that, it's a huge privilege, because you have this player that you're making better and you see the progress, but you also see how she evolves over time as a person. That's very fulfilling for me.
So how has Kostyuk evolved?
"As a player I think she understands what she does on court and what is the best way she can play tennis,” Zaniewska explained.
“She has so many options; like she can hit the ball [hard], she can spin it, she can run all day, she can come to the next, she can do it all.
“I feel like with players like this, it's very tricky for them to really find their identity on the court, and I feel like over the last one-and-a-half years she's been with ups and downs, but she's been finding it better and better.
“Every player has their own game style that's, like, natural for them, and our job as coaches is to bring it out and make it the best that we can.
“So I'm just seeing this grow, and hopefully it continues this way.”
After beginning 2025 inside the top 20, Kostyuk has since slipped to 36th. But it’s been an impressive season nonetheless; in between quarterfinal runs in Doha – where she beat then-world No.3 Coco Gauff – and Madrid were last-16 finishes at Indian Wells and Miami.
She’s back up to 27th in the WTA live rankings and could rise higher if she upstages world No.1 Aryna Sabalenka in the Madrid quarterfinals.
As Kostyuk settles into her position as a regular Grand Slam seed and consistent threat at the biggest tournaments, Zaniewska says the secret to this success is the connection they share.
“We are close, and Marta, she is an emotional player. She probably is more keen on having more conversations with coaches and she needs a little bit more of that, and I feel because of the connection that we have, we're able to do that together,” she explained.
“That definitely has helped us to stay strong for now more than one-and-a-half years already, and hopefully it keeps going.”
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