탄, 하르모니

Tan made her Grand Slam main-draw doubles debut at the 2017 French Open, after having been handed a wildcard to enter the tournament; she and her partner Audrey Albié lost their first-round match to the unseeded pair of Pauline Parmentier and Yanina Wickmayer.

Tan made her Grand Slam main-draw singles debut at the 2018 US Open, where she entered the main draw on a wildcard, losing her first-round match to Eugenie Bouchard, 3–6, 1–6.

Tan made her main-draw singles debut on the WTA Challenger Tour in January 2019 in Newport Beach, where she won her first- and second-round matches (against Katharina Gerlach and Sachia Vickery, respectively) before losing to Taylor Townsend. In May 2019, Tan entered a WTA Tour singles main draw for the first time in her career in Strasbourg thanks to a wildcard; she lost her first-round match to No. 7 seed, Zheng Saisai, 6–7, 6–7.

In 2022, at her first Wimbledon showing, ranked No. 115, Tan defeated Serena Williams in three sets with a super tiebreak 7–5, 1–6, 7–6 (10–7) in the first round after 3 hours and 10 minutes, the longest match thus far at the tournament. After that marathon match she withdrew late, only an hour before her match in the doubles' competition, prompting her partner Tamara Korpatsch to express, in a since-deleted social media post, her anger and disappointment at not being able to participate in the event on her debut. She continued her good run by beating Sara Sorribes Tormo in the second round and home favorite Katie Boulter in the third. Her run came to an end in the fourth round where she fell to 20th seed Amanda Anisimova, in straight sets.

In March 2024, she won the biggest title since Wimbledon 2022 at the ITF W50 tournament in Macon and returned to the top 250 in the rankings.