Chinese teenager Zheng Qinwen sealed the biggest win of her career to-date on Tuesday at the Credit One Charleston Open by taking out 2016 champion Sloane Stephens 6-3, 4-6, 6-0 in the first round. 

Zheng was previous 0-4 in her career against Top 50 opposition, with all four defeats coming this year. Her best previous win in terms of ranking also came on clay, a surface on which she's won four career ITF World Tennis Tour titles: last summer, she beat then-World No.54 Liudmilla Samsonova in Palermo. 

Two of those aforementioned defeats came in heart-breaking three-setters over the past two months, as she was beaten in a third-set tiebreak by Leylah Fernandez in Monterrey and failed to convert a 4-1 final-set lead against Angelique Kerber in Indian Wells, but there would be no third against Stephens. Zheng found her best tennis in the third set, losing just nine points, to complete the 2-hour, 2-minute victory. 

Getting to Know: A big imagination and a bigger game: Inside the rise of Zheng Qinwen

The match had previously halted in the eighth game of the second set, which Zheng serving at 0-15, for over 30 minutes due to a passing patch of rain. 

Charleston: Zheng Qinwen ousts former champ Stephens for first Top 50 win

2022 Charleston

Bencic comes back from the brink in beating Wang Xiyu

Two points from defeat, No.10 seed Belinda Bencic rallied to beat Wang Xiyu, 4-6, 7-6(5), 6-3. Bencic trailed 5-3 in the second set, and 5-2 in the ensuing tiebreak, before coming back in the 2-hour, 26-minute victory. Wang never reached match point.

Bencic, a semifinalist in Charleston in her 2014 debut, also reached the quarterfinals in 2019, but lost in the second round last year to Paula Badosa. To avoid that fate this year, she'll have to stop surging 16-year-old Linda Fruhvirtova, who triumphed in three sets over Ana Konjuh on Monday.

More from Charleston:  Cornet, Fruhvirtova advance; Kvitova succumbs to injury in Charleston

Bencic wasn't the only player to battle back from the brink in Tuesday's day session. Poland's Magda Linette saved a match point en route to defeating American Katie Voleynets, 4-6, 6-3 7-6(5), and she'll be the first opponent for reigning US Open finalist and No.7 seed Leylah Fernandez this week.

Highlights: Bencic def. Wang Xiyu 

After failing to convert her own match point at 5-3 in the decider, Linette saved one on serve at 6-5 before edging the ensuing tiebreak. It's the 23rd match on the Hologic WTA Tour so far this year in which the winner saved match point.

In photos: Great Escapes 2022: Winning from match point down

Riske to be first opponent for top seed Sabalenka

Top seed Aryna Sabalenka will make her Charleston debut against Alison Riske after Riske overcame Caty McNally in an all-American first round, 7-5, 6-3. From 5-4 down in the first set, Riske won seven of the next eight games to wrestle control of the match. 

Riske was one of five Americans who punched their tickets through to the second round in the day session. She was joined by Lauren Davis, CoCo Vandeweghe, Emma Navarro and Hailey Baptiste.

Highlights: Baptiste def. Ruse / Vandeweghe def. Gasanova

Former Top 10 player Vandeweghe, a lucky loser into the draw after the withdrawal of defending champion and expected No.3 seed Veronika Kudermetova, notably scored her first tour-level clay-court win in four years with a 6-3, 4-6, 6-3 victory against Anastasia Gasanova.