The year began with a 21-day quarantine in Melbourne, and by the time Paula Badosa reached Cincinnati in mid-August she was, admittedly, struggling.

The 23-year-old Spaniard had just separated from her coach, Javier Marti, who had guided her way up the WTA rankings ladder. Her aching right shoulder forced a retirement to Karolina Pliskova in the Western & Southern quarterfinals in August. She then lost to No.82-ranked Varvara Gracheva in the US Open’s second round and, three weeks later, to Anett Kontaveit in her second match in Ostrava.

Reunited with her juniors coach, Jorge Garcia, Badosa struggled with an illness, which curtailed her practice preparation in the California desert, even conceding to her boyfriend, Juan Betancourt, that “I’m a little scared of what could happen here.”

“When he saw me a little bit stressed, he was like, ‘OK, this afternoon you’re going to go shopping,’” Badosa said at the time. “Try to disconnect and be a little bit happy outside because sometimes I get too negative and very worried before the tournaments.”

Badosa then went out and won all six of her matches at the BNP Paribas Open, beating three major champions in the process, including Victoria Azarenka in the final. After starting the season at No.70, she’s a newly minted member of the Top 10 and one of the eight singles players at the Akron WTA Finals Guadalajara.

WTA Finals Day 4 order of play: Sakkari and Badosa look for spot in semis

“I will try not to get emotional,” she said Monday in her pre-tournament press conference, “but I’ve been through a lot. I’m very proud of myself. I think I did a very good year. It always has been a dream to me to be in Top 10, one of the best players in the world. Now it’s coming true.”

Overall, it had been a terrific, groundbreaking year for Badosa. On Thursday, she easily took care of Aryna Sabalenka in straight sets in their opening round-robin match at the WTA Finals.

Badosa has wins against World No.1 Ashleigh Barty, Olympic gold medalist Belinda Bencic and French Open champion Barbora Krejcikova, while reaching the Roland Garros quarterfinals (a career-best run at a major), the Madrid semis as well as winning her first WTA title, in Belgrade.

In the days leading to the Finals, Badosa and her colleagues cut a huge swath in Guadalajara, amid glitz and glam, dressing to the nines for the WTA Finals Gala and draw ceremony. But the everyday reality – where stress and anxiety are a constant companion – is quite different. In tennis, the rankings come out on Mondays and everyone knows where you stand.

Road to the WTA Finals: Badosa emerges as all-court threat in breakout season

In one of the most physically demanding sports, mental fitness is just as important. Maybe more so. Previously not a topic for public discussion, mental health issues were widely seen in the athletic establishment as a sign of weakness. Today, it finally has entered the mainstream conversation.

For a number of reasons, it’s been a difficult year in professional tennis. These eight players managed to navigate the issues – some unprecedented and some more familiar. It meant overcoming the global pandemic and, in some cases, even their own success.

The spread of COVID-19 posed complicated logistic problems for the global citizens who play tennis for a living. Twenty-six women’s singles players at Australian Open were in 14-day quarantine because of close contact with someone who tested positive. Four of them reached Guadalajara – Maria Sakkari, Kontaveit, Krejcikova and Badosa.

"I've been through a lot," Badosa said Thursday after her win against Sabalenka. "When I was very young I didn't have these expectations, but I had a lot. I did it totally wrong. I went the way that wasn't the correct one. After some years I learned a lot."

Badosa was a junior Grand Slam champion, at Roland Garros in 2015. She was 17 and already marked as a potential future major champion. She grappled with depression early in her career – and the enormous expectations her abilities suggested.

After she reached the Round of 16 at the first event of 2021 in Abu Dhabi, her then-coach Javier Marti told her she could finish in the Top 30.

“I was like, `That’s impossible to finish the year Top 30,” Badosa said. “Top 50, I can sign here. Imagine I finished the year Top 10. What can I say?”

The doubts that she belonged among this company have been replaced by a new kind of pressure.

“It was quite stressful,” she said of the aftermath of her Indian Wells triumph. “I know it was my first time winning a big tournament, so a lot of new things." 

It took her 10 days to finally feel relaxed.

“I had to do a lot of things,” Badosa said. “It was a big change. But I know it’s like that. After here I need to be calm a little bit, at least one week, think about everything that have happened.”

On Saturday, Badosa will face Sakkari, with the winner advancing to the semifinals of the year-end championships. Badosa, as much as anyone in the field, understands how precious these moments are.

 "It's very complicated to stay in the top," she said. "I think you need to have a stability in your life, be happy outside the court. I think on court you have to work very hard every day.

"Even though now I'm a Top 10 player, it's impossible to relax. You're Top 10 today but tomorrow you're out of there, you stop working. I have that very clear."