Another factor is having a hitting partner – a role almost exclusively filled by men.
While the biggest stars often travel with both a coach and a hitting partner, many players on tour cannot afford to bring both to every event. As a result, they opt for a coach they believe can fill both roles.
Given that women compete against other women, why is a male hitting partner considered essential? Perhaps it’s not just the extra power and top spin on their shots, but the confidence they exude.
“Sometimes we laugh that you can have male hitting partners and their ego is so big – they come and just think they know everything,” Zaniewska, 34, said.
“When you’re top 100 or top 50, so much is about the mental game and believing in yourself and projecting confidence.
“On that level it helps, because if you have a player that does not feel that you’re confident and [that] you believe in them and yourself – because it goes together – then they’re going to feel it very quick.”
A high level of self-belief is something Martinez has been able to transfer to Andreeva.
“She understands me more than anyone could,” the Russian teenager said 12 months before her triumph at Roland Garros.
“She’s been through this. She’s also a woman. She’s played so many matches on tour, she’s so experienced. She’s a Grand Slam champion.”
Zaniewska believes female coaches can sometimes be judged unfairly because they express confidence differently.
“It’s not that females are more insecure, I wouldn’t say that,” Zaniewska said.
“We just think more, so we’re more conscious of things. We really want to make sure that we figure it out before we give advice to someone.
“That can portray a sense of insecurity sometimes.”