No.12 seed Paula Badosa held off Leylah Fernandez 7-5, 7-6(6) in 1 hour and 51 minutes to reach the third round of the Credit One Charleston Open for the third time in as many appearances.

She will face fast-rising 19-year-old Diana Shnaider, who knocked out No.5 seed and former champion Veronika Kudermetova 6-4, 6-3 in 1 hour and 34 minutes.

Badosa came from 3-0 down in the first set and saved one set point in the second-set tiebreak to improve to 3-0 against Fernandez, whom she had previously defeated in 2020 Auckland qualifying and Indian Wells 2022.

"We always have battles," said Badosa afterwards. "She plays so fast, she doesn't give me time. She was playing unbelievable, especially at the start. In the last games of the second set she started to go on the lines again.

"At the beginning I wasn't expecting that she'd start that well. I thought, OK, you have to serve very well and go for the shots before her. I started to be a little more aggressive, and it worked."

Keys to the match: As Badosa suggested, Fernandez raced out of the blocks. Taking the ball early and conjuring up all manner of angles, she won 12 of the first 15 points and left the Spaniard flat-footed.

But the 2021 US Open finalist wasn't able to sustain her high-risk strategy. A double fault handed the break back, and the forehand that had initially racked up winners began to go awry at the end of the first set and start of the second as she fell down 4-2.

Fernandez's 31 winners included a series of exquisitely spun volleys, and her forehand began to light up the court again as she broke Badosa back and forced a tiebreak. But 30 unforced errors meant that she was always walking a tightrope compared to the steadier Badosa, who tallied 15 winners and 18 unforced errors.

Badosa did find a forehand winner to save set point, and reached match point after a net cord took Fernandez's drive volley over the baseline. The former World No.2 converted it with her fourth service winner of the tiebreak -- another crucial element of her victory.

Charleston: Shnaider upsets former champ Kudermetova for first Top 20 win

Shnaider hitting milestones rapidly: Shnaider made waves at the Australian Open in January when she qualified for her first tour-level main draw and stretched Maria Sakkari all the way in a 3-6, 7-5, 6-3 second-round loss.

A first Top 20 win eluded the powerful left-hander in Melbourne, but it hasn't taken her long to score her first statement victory. Charleston is only Shnaider's third tour-level main draw, and Kudermetova only the second Top 20 player she had faced following Sakkari.

No.95-ranked Shnaider is mixing her first Hologic WTA Tour season with her freshman year at North Carolina State University, where she is majoring in biology. She had lost three straight matches in February and March, but has looked in her element on the green clay this week.

Shnaider came from a break down in both sets to defeat Kudermetova, who won her first title in Charleston in 2021. The teenager fired 19 winners in total -- mostly from her formidable forehand, but also coming up with touch at net and on the drop shot.