[citation needed] Playing with Anastasia Potapova, Sizikova won her first WTA Tour title at the Ladies Open Lausanne, defeating Monique Adamczak and Han Xinyun in the final.

[1] In June 2021, she was arrested at Roland Garros after her French Open doubles first-round loss, amid a match fixing in tennis investigation from previous year's tournament.

[citation needed] Partnering with Han Xinyun, she was runner-up in the doubles at the 2022 Monterrey Open, losing the final to Catherine Harrison and Sabrina Santamaria.

[7] Partnering with Kimberley Zimmermann, Sizikova won the doubles at the Palermo Ladies Open, overcoming Angelica Moratelli and Camilla Rosatello in the final.

[10] Teaming up with Alexandra Panova, she also won the doubles title at Palermo Ladies Open for the second year in a row, defeating Yvonne Cavallé Reimers and Aurora Zantedeschi in the final which went to a deciding champions tiebreak.