[citation needed] Cristian reached her maiden WTA Tour final at the 2019 Bucharest Open in the doubles event, again partnering Ruse.

[7] At the Upper Austria Ladies Linz, she reached the final as a lucky loser following Halep's withdrawal due to injury from the semifinal[8] but lost to Alison Riske in three sets.

[citation needed] Cristian made her Grand Slam tournament debut in Melbourne, at the Australian Open[10] where she won her first round match against Greet Minnen,[11] before losing to Madison Keys.

[citation needed] She made her WTA 1000 debut at the Qatar Open as a lucky loser and defeated 11th seed Elena Rybakina for her first win at this level.

[23] At the 2024 Palermo Ladies Open, Cristian defeated Lucia Bronzetti[24] to make it through to the quarterfinals where she lost to top seed and eventual champion, Zheng Qinwen.

[26] In September 2024, at the WTA 1000 China Open, Cristian reached the third round for the third time at this level with her first career upset over a top 10 player, reigning Wimbledon champion Barbora Krejčíková, in three sets saving four match points.

[34] Cristian started her 2025 season at the ASB Classic in Auckland, where she advanced to the second round after her opening opponent, Yuliia Starodubtseva, retired due to injury.

[36] At the Australian Open, Cristian reached the third round of a Grand Slam tournament for the first time in her career, defeating lucky loser Petra Martić[37] and Lucia Bronzetti.