On Dec. 31, as the final hours of 2021 ticked away, Naomi Osaka wrote on Twitter: “I’ve never been more excited for a year to be over.”

Osaka, who had not played a competitive tennis match since losing in the third round of the U.S. Open to the world’s 73rd-ranked player, was getting a jump on the start of 2022 in Melbourne, Australia, after her second lengthy break from the game in seven months. And who could blame her.

In the 10 months since she won her fourth Grand Slam title, in Australia, her destiny had gone from can’t-miss superstardom to something far more concerning.

As last winter closed, Osaka was the dominant figure in her sport and the world’s highest paid female athlete at just 23 years old, as well as a respected voice on social justice issues. And then she became something else entirely.

“There was a time after the French Open where I felt like everyone was judging me,” she said after her first-round win at the Australian Open Monday. “It feels a bit weird when you go into a stadium to play and you’re kind of concerned what everyone’s gaze means.”

Her game began to unravel in the early spring, especially as the competition moved to clay, where she has never been comfortable. A confrontation with French Open officials over her refusal to appear at mandatory postmatch news conferences led to her withdrawal from the tournament. She went public with her yearslong battle with depression, took two months off, then returned at the Tokyo Olympics, where she lit the torch but lost in the third round amid relentless pressure to excel.

Then came the upset in the U.S. Open, where she was a favorite to successfully defend her title, but exited with a tearful admission that playing tennis no longer made her happy, if it ever did. Suddenly, that moment of triumph at the 2020 U.S. Open felt ominous: After prevailing in three sets, she barely smiled and instead lay in the center of the court, staring at the dark sky.

“It was just like an extreme buildup, and you just happened to see it all release last year,” a rusty Osaka said this month, after her first tuneup match in Melbourne, a messy three-set win over Alizé Cornet.

Osaka grew sharper, and calmer, in her next two matches, both straight-set wins, then pulled out of the warm-up tournament ahead of her semifinal, saying her body was in shock after playing three matches in five days after a layoff that she had expected to last much longer.

“I actually really thought I wasn’t going to play for most of this year,” she said. “I was feeling kind of like I didn’t know what my future was going to be. I’m pretty sure a lot of people can relate to that.”

In some ways, relating to Osaka, who plays Madison Brengle in the second round at the Australian Open on Wednesday, has never been easier. Her story — though no one knows how it will end — is a cautionary tale for anyone pursuing a dream that may not be her own or for anyone who needs to press the pause button, regardless of the consequences.

Despite her vast wealth and early success, or perhaps because of them, she has never seemed more vulnerable. And yet there will always be a remove with Osaka, who can be painfully shy, a kind of wall that even people who have been close to her have struggled to break through. That has only gotten more difficult as her persona has grown, because so have the barriers and the team of gatekeepers surrounding her as the pressures of success and fame mount.

“In some ways, this all can be easier with a more outgoing person,” said Harold Solomon, the former pro who coached Osaka when she was a teenager. “Naomi is quiet and introspective. I’m not sure if she was really clear of what all of this would mean.”

Now, back in Australia, the place where things last appeared right in her world, is she ready for the crucible? Even if she prevails, in matches, in the biggest tournaments, is that an appropriate way to measure the success and well-being of someone who just four months ago could not find joy on a tennis court? Is this really the life Osaka wants?

Osaka, a self-described introvert, rarely grants interviews. She speaks in tightly controlled settings or postmatch news conferences during tournaments, where she has said she would prefer not to appear. (It’s also possible that her complaints about news conferences were merely a vessel for her larger complaints about the life of a pro tennis player.)

Her parents, including her father, Leonard Francois, who pushed his daughters to pursue tennis, following the blueprint of Richard Williams, no longer speak publicly. Osaka declined through her representatives to be interviewed for this article. Behind microphones, she communicates deliberately, in clipped phrases that are turned over and over. When she has emoted, it has usually been on Instagram or Twitter.

Sascha Bajin, who coached Osaka to her first two Grand Slam titles, at the 2018 U.S. Open and the 2019 Australian Open, said he initially had to figure out how to get her to trust him enough to participate in the most basic communication.

“Naomi was so shy in the beginning, she didn’t even talk,” he said in a recent interview. Bajin noticed that she liked anime. So he began watching it, and learning about it, then made casual references to it before or after practice, which began to draw her out. “She saw that I showed interest in something that interested her. With Naomi it takes trust and belief.”

Never celebrated winning points or games.

There is a very basic and fair question to ask when considering Osaka’s career: Does she actually like tennis? Did she ever?

“Yeaahhh?” Solomon said in a singsong, the way people intonate when they are not quite convinced of what they are saying.

Solomon was one of several South Florida coaches who shared his services at little or no cost to help Francois fulfill his dream of producing the next iteration of Venus and Serena Williams.

Mari, who is 18 months older than Naomi and as free with her emotions as Naomi is bottled up, initially had more drive to achieve stardom, Solomon and the other coaches said. She ultimately lacked the size, speed and power of her younger sister, who at 5 feet 11 inches is about a half-foot taller. Mari Osaka’s singles ranking peaked at 280 in 2018. She retired last year.

Her younger sister’s motivations were more of a mystery.

Bill Adams, who coached the girls when the family first moved to Florida from New York in 2006, said Naomi Osaka was tough to read even as a 10-year-old. She never refused to do a drill or “made a face,” Adams said, but she never celebrated good shots or winning points or games. A dozen years later, Adams ran into Osaka at the Evert Tennis Academy after she won the Indian Wells Masters, the first significant title of her career.

“I told her I was pleased because I didn’t think you really liked it in the beginning,” Adams said.

For years, the coaches said, beating her older sister was Osaka’s primary motivation. Once that became possible, her dreams expanded. Patrick Tauma, who coached the Osaka girls when Naomi was in her midteens, said he once asked her what she dreamed of accomplishing on the tennis court. She told him it was to beat Serena Williams in the final of the U.S. Open.

She accomplished that in 2018, but the win was somewhat tarnished by Williams’s meltdown amid confrontations with the chair umpire, who penalized her for receiving coaching during the match. At the trophy ceremony, Osaka was in tears.

“I feel like she lost her purpose,” Tauma said. “She is so young. It all went so fast for her.”

Osaka’s relationship with Solomon, who coached her when she was 16, was less harmonious. It ended not long after he questioned her definition of working hard, every day. He said the dynamic of their relationship was backward, with the coach pulling the student instead of the other way around.

“I’m not saying it wasn’t there at times, but to bring out the full potential, you need to do that on a consistent basis,” Solomon said. “She was young, I was maybe too impatient, but I’m not going to spend time on the court with you if you are not willing to do that.”

Work, wins, and then a crash.

Clearly, Osaka figured out how to work hard consistently enough to win four Grand Slam titles, but eventually winning offered relief rather than happiness or fulfillment, despite the money, fame and platform that it also gave her.

Did she understand everything that would come with her success on the court, Tauma wondered — the heat of the spotlight, the obligations to sponsors, the weight of being a symbol of a new, more multicultural and open Japan?

“She just wants to be a tennis player,” Tauma said. “Now she is a money machine. All these people working around her like a company. She feels like I am not a player anymore.”

In the fall, he reached out to Osaka’s team and offered to spend a little time on the court with her as a way of getting back to her roots and remembering the good things about the game and “the smell of when you were starving.” Tauma never heard back.

At the time, Osaka was busy with things she did not get to do growing up, like driving from her home in Los Angeles to the Bay Area to have sleepovers.

“I didn’t really have that many friends, so I didn’t really talk to anyone,” she said.

Eventually her desire to be on the court once more returned. She texted her coach and trainer and asked if they would be willing to work with her again. “I was just sitting in my house wondering, what do I want to do in the future?” she said. During her first practices, she tried to be acutely aware of whether she wanted to be there, whether she could be fully committed in each moment, because if she did not, she knew she was wasting everyone’s time.

“I’m not sure if this is going to work out well,” she said this month in Melbourne.

Osaka was mostly solid in her first-round win over Camila Osorio of Spain. She said that she often feels happy starting the year in Australia. Whether she can stay that way is anyone’s guess.