The top two seeds, Aryna Sabalenka and Paula Badosa, clinched second-round wins at the Credit One Charleston Open on Wednesday.

Sabalenka was challenged by former Top 20 player Alison Riske, but the No.1 seed pulled through with a 7-6(3), 6-4 victory after 1 hour and 49 minutes of play, ending a three-match losing streak.

Sabalenka had beaten Riske in all of their previous meetings — including in two Hologic WTA Tour singles finals in 2019 — and she extended her undefeated record over the American to 5-0 on Wednesday.

More from Charleston on Wednesday: Pliskova grabs first win of the year

The first set nearly got away from Sabalenka, who saw four set points slip away at 5-4. Riske dragged Sabalenka into a decisive first-set tiebreak, where Sabalenka at last converted her sixth set point after a long volley miscue by Riske.

After the 64-minute opener, Sabalenka had things well in control in the second set up to 5-2. But once more, Sabalenka failed to close out the match in that game, and Riske eased to 5-4.

Riske had four break points in that game to completely level the set, but Sabalenka used her power game to its greatest effect when it counted most, swatting those chances away and gritting out the hold to collect victory.

Sabalenka will next meet No.15 seed Amanda Anisimova in the Round of 16. Anisimova has won both of their previous meetings, which came at the Australian Open and Roland Garros in 2019.

Later on Wednesday, No.2 seed Badosa eased into the Round of 16 with a 6-1, 6-4 win over Anna Bondar. Badosa, a semifinalist in Charleston last year, had to overcome a mid-match rain delay before prevailing in 1 hour and 35 minutes.

A speedy first set was followed by a much tighter affair in the second, where Bondar fought back from an early break down. However, Badosa prevailed on her fifth break point of a long game to break for 5-4, and served out the match from there.

Highlights: Badosa def. Bondar

Awaiting Badosa in the Round of 16 is 2017 Junior Wimbledon singles champion Claire Liu of the United States. World No.89 Liu upset No.16 seed Zhang Shuai 7-5, 2-6, 6-4 on Wednesday.

Despite the disparity between their current rankings, Liu has beaten Badosa in both of their professional meetings, and both wins came on clay. Liu defeated Badosa in the final of an ITF Challenger event in Caserta, Italy in 2017, and again in Bucharest qualifying in 2018.

Bencic holds off rising teen Fruhvirtova

No.10 seed Belinda Bencic also booked her spot in the third round by fending off 16-year-old Czech Linda Fruhvirtova 6-1, 7-6(6).

Highlights: Bencic def. Fruhvirtova

Teen sensation Fruhvirtova is up to a career-high ranking of World No.188 after a run to the Miami Open Round of 16. But reigning Olympic gold medalist Bencic stopped the teenager's run after 1 hour and 39 minutes, making it into the Round of 16 in Charleston for the third time.

Bencic had to battle in the second set, where Fruhvirtova built an early 3-0 lead and served for the set at 5-4. But Bencic broke the teen in that game before holding on in the tiebreak to prevent a third-set showdown.

Next up for Bencic will be an encounter against the player directly in front of her in the seedings, 2019 Charleston champion and No.9 seed Madison Keys. Keys leads their head-to-head 2-1.

Kalinina ousts Rybakina for first Top 20 win

Another seeded player, though, suffered an upset on Wednesday afternoon, as Anhelina Kalinina knocked out No.5 seed Elena Rybakina 6-4, 2-6, 6-4 in 2 hours and 18 minutes.

Highlights: Kalinina def. Rybakina

World No.42 Kalinina of Ukraine, who also hit a new career-high ranking this week, continues her rise with her first win over a Top 20 opponent in her career.

Kalinina will go for a second consecutive upset over a seed when she takes on No.12 seed Alizé Cornet in the Round of 16.