In an era of regimented game plans, strict training regimes, nutritionists and pre-match routines, one player is refreshingly going her own way -- Hsieh Su-wei.
"She's a free spirit," said long-time coach Paul McNamee after Taiwan's Hsieh became the oldest woman in the Open era to debut in the quarter-finals of a Slam.
"That's the same with her tennis. She kind of acts on a whim sometimes, doesn't like to plan too far ahead."
Australian Open wins over Tsvetana Pironkova, eighth seed Bianca Andreescu, Sara Errani and Marketa Vondrousova mean that the maverick will face Naomi Osaka, 12 years her junior, on Rod Laver Arena on Tuesday for a place in the semi-finals.
"To think she's 35 years of age, in her first Grand Slam quarter-final," McNamee said.
"I always believed she had a Grand Slam quarter at least in her, quarter or a semis. She's achieved that now. She ticked that box."
McNamee, who has coached Hsieh since 2011, said he never knows what will happen next.
"She was playing a match in Eastbourne one day," he recalled.
"She missed two balls in a row by three metres. I noticed she was playing with broken strings," said McNamee.
"She hadn't broken a string for three years. She didn't know what it was like.
"Players change racquets on the change of balls, right? She'll go years with the same racquet."
Eccentric or not, Hsieh's natural talent was clear to see when she made her professional debut at the age of 16 in 2001.
Double-handed on both forehand and backhand sides, Hsieh went unbeaten in her first 33 matches on the ITF circuit and won five consecutive titles as a qualifier.
- 'The joy of silence' -
But it wasn't until Hsieh linked up with McNamee in 2011 that she began to handle life on tour -- and her career flourished.
"Before I worked with him, I have a lot of time alone," said Hsieh about Australian McNamee, a former ATP Tour player.
"That was why it was not easy to improve or to find a way out. Sometimes, I had no one to warm up with."
Hsieh broke through at the highest level when she won the Wimbledon doubles in 2014 with China's Peng Shuai.
The pair won the French Open the following year. Then with Barbora Strycova she won a second Wimbledon in 2019 and ended 2020 ranked world number one in doubles.
McNamee was quick to credit Hsieh's French boyfriend, Frederic Aniere, who has helped with coaching over the past few years, as the ageless Taiwanese reached new heights.
"It's nice of her to give me some credit, but really Fred has been the one that's helped her actually be more professional, if I can say that," McNamee said.
"They live together in Paris. She likes Paris. Fred has been an amazing influence on Su-wei the last few years. It's a team effort absolutely."
World number 71 Hsieh, as befitting her laid-back attitude, is unflustered in exalted company.
She beat then world number one Simona Halep at Wimbledon in 2018 and now has 16 wins over top-20 players, 10 of them coming in the past two seasons.
She will be looking for another against Osaka, having knocked her out of the Miami event in 2019 -- a second victory for Hsieh over a reigning world number one.
McNamee says his job is often simple, dispensing with the highly detailed analysis that some coaches employ, and just allowing the freestyling Hsieh to be herself.
"Sometimes you just have to back off and say nothing," said McNamee. "I've learnt the joy of silence a lot working with Su-wei.
"You don't want to put that talent in a box. You've got to let it rise and be free.
"There's only one Su-wei."