NEW YORK, NY, USA - Trust and communication are some of the biggest keys for any healthy relationship, but when it comes to the WTA’s top doubles teams, knowing when to spend some time apart might just be the most important factor in a successful partnership.

Trusting a partner to prepare for and recover from a match independently of the other takes trust, said Ashleigh Barty, who is partnered with CoCo Vandeweghe as the No.13 seeded team, but that’s part of what translates to their on-court understanding.

Read more: Vandeweghe, Barty upset Strycova, Sestini-Hlavackova, into US Open quarterfinals

“On the court we do what we do, and then off the court with recovery and everything you go off with your teams and do what you need to do,” Barty explained. But then in a sense, we also prepare together.

“I mean, I know that CoCo trusts me and I trust CoCo to be ready to play, prepare and do what we need to do. And then obviously, before we go out there we have a quick chat about the match and work out how we want to play.”

The pair are close friends, and started their successful doubles partnership with a title in Miami, but even still they prefer to only see each other in limited doses while in New York City.

“I’ve been busy playing singles in this one,” Barty said; the Australian reached the fourth round while Vandeweghe fell in her opening match. “But now that we’re both just focusing on doubles, I think she can put up with me on a practice day…”

“One!” Vandeweghe interrupted with a laugh.

Nicknamed the "Angry Birds," Czech duo Barbora Strycova and Andrea Sestini-Hlavackova, the No.3 seeds, have plenty in common - both hail from Pilsen, are self-described “foodie girls”, and claimed their first title as a team at the Connecticut Open in New Haven.

But they were emphatic that they key to translating their friendship into doubles success is not to force ‘together’ time during their scant days off.

“At Grand Slams, I prefer to have my alone time, honestly,” Sestini-Hlavackova said. “And I like to just look forward to see Bara next day.”

Read more: Mladenovic, Babos outlast Hradecka, Makarova at US Open

“In this weather, I try to do nothing [on my days off],” Strycova added, referencing the brutally hot temperatures and high humidity. “But I am a person who likes food and who likes coffee, so I always try to discover new spots - in SoHo or around my hotel. But that’s kind of it - I’m here to play tennis, and once I’m done here I can do something else.”

She added, “We are not like, ‘Oh we are not going to do dinner tonight.’ We just go if we both feel like going, but if not we just don’t go. It’s very relaxed.”

Veteran doubles stars like Ekaterina Makarova and Lucie Hradecka, who lifted the trophy in Cincinnati and were the US Open’s No.6 seeds, shared a similar sentiment. Their partnership is fairly recent after a long-term injury to Makarova’s longtime partner, Elena Vesnina, has left her sidelined since Roland Garros, and the Czech-Russian duo view themselves more like coworkers than anything else.  

“We are both of us very good doubles players, and [have both] had great results in the past,” Makarova said. “I would say we are working teammates. Co-workers, because we have our own time and then we’re here at our workplace.”

Hradecka agreed, saying, “Especially here where the hotel is like one hour, 45 minute drive, and we are staying at different places, it makes it very tough to set up some dinner or something like that.

“We haven’t had too many easy, easy days. But I think me and Katya know how to do our best on the court, so when it’s a day off we can just do what we want to do and be ready for the next match.”

Even No.2 seeds Kristina Mladenovic and Timea Babos, who have known each other since they were 10 and are such good friends that they consider each other like more like family, prefer to cultivate their interests independently off the court: while Mladenovic enjoys visiting art galleries with her mom, Babos will take in one or two musicals on Broadway.

“It’s pretty natural, because honestly I think we have the same personalities,” Mladenovic said. “So I think we both feel it when we need preparation or we want to do something different.”

“I feel like we’re the same blood; sometimes we don’t even text because we know, ‘Oh I feel like nothing is happening today.’ We are both always in the same mood and so it’s super easy for us,” Babos added.