A junior Grand Slam tournament runner-up in both singles and doubles, Yastremska had a quick breakthrough onto the WTA Tour.

On 22 June 2021, the International Tennis Federation ruled that Yastremska was not responsible for the positive result, and that she was eligible to return to competition immediately.

She made her debut at the highest-level Grade A tournaments in October, reaching the quarterfinals at the Osaka Mayor's Cup in Japan.

[9] In doubles, she made it to the final, losing to Anna Kalinskaya and Tereza Mihalíková alongside compatriot Anastasia Zarycká.

In the doubles event, she partnered with Panna Udvardy to win the only Grade A title of her career, defeating the American team of Caty McNally and Natasha Subhash.

[17] A year later, Yastremska was awarded another wildcard into the same tournament and defeated Andrea Petkovic for her first career WTA match win.

[21] Yastremska also had a strong season in doubles, winning three ITF titles, including the $80k Prague Open with Anastasia Potapova.

[28] The following week, she made her Grand Slam main-draw debut and was upset in her opening-round match by qualifier Karolína Muchová.

After a quarterfinal appearance at the Hobart International, she won her first two Grand Slam main draw matches at the Australian Open before losing to Serena Williams in the third round.

[21] Following this title, however, she began to struggle and only tallied one match win in her next six tournaments in part due to playing through an ankle injury.

[35] While she lost her opening-round match at the French Open to Carla Suárez Navarro,[36] she reached the fourth round at Wimbledon, her best Grand Slam result to date.

[37][38] In the second half of the season, Yastremska produced another good performance at a major at the US Open, losing in the third round to compatriot and world No.

They upset top seeds Hsieh Su-wei and Barbora Strýcová in their second match before finishing runner-up to Kenin and Bethanie Mattek-Sands.

[42][43] At the end of season, Yastremska unexpectedly qualified for the WTA Elite Trophy, the second-tier year-end championships, after several higher-ranked players withdrew from consideration.

[46] At the Australian Open, she beat Kaja Juvan in the first round, before falling to Caroline Wozniacki in the second, the Dane's final tournament victory before her retirement.

First-round losses in Ostrava and Linz completed a disappointing end to the season, one in which her only success in doubles was a win in the Fed Cup tie against Estonia.

On 7 January 2021, the ITF announced that, in November 2020, Yastremska had tested positive for a metabolite of mesterolone, an anabolic steroid medication which is prohibited by WADA.

The ITF announced that, as a result of testing positive for this banned substance, Yastremska shall be provisionally suspended, "pending determination of the charge against her at a full hearing".

[54] On 22 June 2021, the ITF ruled that Yastremska "bore no fault or negligence" for the positive test result, and announced that her provisional suspension would be lifted with immediate effect.

Her next tournament was at the Tokyo Olympics, where she suffered two first-round defeats: to Leylah Fernandez in the singles event, and, partnering Elina Svitolina, to Alizé Cornet and Fiona Ferro of France in the doubles competition.

After losing in the first round at the Kremlin Cup, she reached the quarterfinals at the Courmayeur Ladies Open in a rematch against Paolini and lost in straight sets.

She played as Ukraine's top seed in the Billie Jean King Cup qualifiers, in a tie against the United States.

[64] She became just the second qualifier in the Open Era to defeat two former Grand Slam champions at a major since Jelena Dokic who upset Martina Hingis and Mary Pierce at Wimbledon in 1999.

[74] As top seed, Yastremska defeated Katie Volynets[75] and qualifier Ann Li to reach the quarterfinals at the Hobart International,[76] where she lost to eventual champion McCartney Kessler.

[95] At the 2019 Australian Open, Yastremska's mother suffered an eye injury after a champagne bottle that she was holding exploded unexpectedly.

She had immediate surgery to save her eye, which was coordinated in part by Elina Svitolina's agent Stefan Gurov and financially covered by tournament director Craig Tiley.

[96][97] On 9 July 2020, in the wake of the murder of George Floyd in Minneapolis, Minnesota, world-wide protests, and increased visibility of the Black Lives Matter movement, Yastremska posted four images of herself to her Twitter and Instagram accounts of her sporting half-white, half-black makeup, with the caption "Equality".

Yastremska was widely criticised on social media, with many pointing out that her sporting blackface was antithetical to the message she was attempting to convey.

[98] During the 2022 Russian invasion of Ukraine, Yastremska fled to France for safety, alongside her younger sister, Ivanna, on 26 February, being forced to leave her parents behind in her hometown of Odesa.

[99] Yastremska has been accused of gamesmanship by commentators and fellow players, and for allegedly exaggerating and faking injuries to exploit the medical time-out system.