In the competitive world of women’s tennis coaching, Sandra Zaniewska stands out not only for her tactical work but also for her unique approach that interlaces sport and introspection. The 34-year-old Polish coach has guided Ukrainian star Marta Kostyuk, 24, from a promising athlete struggling to unlock her potential into a formidable contender currently ranked No. 12, who reached the quarterfinals at Wimbledon this year.

Kostyuk’s recent run at Wimbledon included a victory over American qualifier Ashlyn Krueger in the fourth round, advancing her to face No. 13 seed Jasmine Paolini. Her performance has been remarkable, winning 20 of her past 21 matches. Kostyuk credits her progress to meeting Zaniewska three years ago for a conversation in London that eventually led to their coaching partnership.

While Zaniewska’s impact on Kostyuk’s game is widely recognized, the coach’s deeper passion lies in writing. Her ambition to become a novelist dates back to childhood, sparked by an encouraging school experience when an early essay earned her an A+ and inspired her to pursue creative storytelling. Though Polish is her first language, Zaniewska writes primarily in English, which she has spoken since her teenage years training abroad.

Zaniewska shares insights into her coaching philosophy in her newsletter, “The Unseen Court,” which explores the mental and emotional complexities of coaching at the highest level. She emphasizes the importance of restraint, arguing that effective coaching often means knowing when not to intervene. In one recent essay, she noted that coaches can be correct in their observations yet still unhelpful if timing and manner do not align with the player’s state, underscoring the subtle balance between guidance and space.

Her writing has drawn comparisons to other tennis figures such as Andrea Petkovic and Claire Liu, who also publish personal reflections. Zaniewska’s narratives provide an intimate view into how she and Kostyuk navigate challenges beyond the court, including emotional resilience and identity separation amid pressures.

Kostyuk, a Kyiv native whose family remains in Ukraine amid ongoing conflict, speaks openly about the role Zaniewska plays—as more than a coach, an “elder sporting sister”—and expresses appreciation for how their relationship is captured through these essays. She often references their growth—not as a sudden breakthrough but a steady building of conditions that allow her best level to become more consistent under pressure.

Earlier this year, after back-to-back tournament wins in Rouen and Madrid, Zaniewska wrote about dispelling the myth of sudden success in tennis, emphasizing instead the long effort to stabilize performance under challenging circumstances.

As Zaniewska and Kostyuk approach their three-year partnership milestone, Zaniewska continues to reflect on the evolving nature of their relationship and the lessons learned both on and off the court. Their journey underscores the complexities of elite sports coaching, where progress intertwines with self-discovery, patience, and the ongoing search for reliability in a volatile game.

At Wimbledon, Kostyuk overcame her doubts about her grass-court abilities with Zaniewska’s candid reassurance, a moment she described as pivotal. Her unexpected advance to the second week of the tournament marked a milestone that once seemed out of reach, demonstrating the tangible impact of their collaboration.

Zaniewska’s dual role as coach and writer offers a fresh perspective on the nuanced mental dimensions of tennis, illuminating how the mind’s narratives shape both performance and personal growth in the sport.